path: root/framework/Web/UI/TControl.php

<?php
/**
 * TControl, TControlCollection, TEventParameter and INamingContainer class file
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2014 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @package System.Web.UI
 */

/**
 * Includes TAttributeCollection and TControlAdapter class
 */
Prado::using('System.Collections.TAttributeCollection');
Prado::using('System.Web.UI.TControlAdapter');

/**
 * TControl class
 *
 * TControl is the base class for all components on a page hierarchy.
 * It implements the following features for UI-related functionalities:
 * - databinding feature
 * - parent and child relationship
 * - naming container and containee relationship
 * - viewstate and controlstate features
 * - rendering scheme
 * - control lifecycles
 *
 * A property can be data-bound with an expression. By calling {@link dataBind},
 * expressions bound to properties will be evaluated and the results will be
 * set to the corresponding properties.
 *
 * Parent and child relationship determines how the presentation of controls are
 * enclosed within each other. A parent will determine where to place
 * the presentation of its child controls. For example, a TPanel will enclose
 * all its child controls' presentation within a div html tag. A control's parent
 * can be obtained via {@link getParent Parent} property, and its
 * {@link getControls Controls} property returns a list of the control's children,
 * including controls and static texts. The property can be manipulated
 * like an array for adding or removing a child (see {@link TList} for more details).
 *
 * A naming container control implements INamingContainer and ensures that
 * its containee controls can be differentiated by their ID property values.
 * Naming container and containee realtionship specifies a protocol to uniquely
 * identify an arbitrary control on a page hierarchy by an ID path (concatenation
 * of all naming containers' IDs and the target control's ID).
 *
 * Viewstate and controlstate are two approaches to preserve state across
 * page postback requests. ViewState is mainly related with UI specific state
 * and can be disabled if not needed. ControlState represents crucial logic state
 * and cannot be disabled.
 *
 * A control is rendered via its {@link render()} method (the method is invoked
 * by the framework.) Descendant control classes may override this method for
 * customized rendering. By default, {@link render()} invokes {@link renderChildren()}
 * which is responsible for rendering of children of the control.
 * Control's {@link getVisible Visible} property governs whether the control
 * should be rendered or not.
 *
 * Each control on a page will undergo a series of lifecycles, including
 * control construction, Init, Load, PreRender, Render, and OnUnload.
 * They work together with page lifecycles to process a page request.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
class TControl extends TApplicationComponent implements IRenderable, IBindable
{
	/**
	 * format of control ID
	 */
	const ID_FORMAT='/^[a-zA-Z_]\\w*$/';
	/**
	 * separator char between IDs in a UniqueID
	 */
	const ID_SEPARATOR='$';
	/**
	 * separator char between IDs in a ClientID
	 */
	const CLIENT_ID_SEPARATOR='_';
	/**
	 * prefix to an ID automatically generated
	 */
	const AUTOMATIC_ID_PREFIX='ctl';

	/**
	 * the stage of lifecycles that the control is currently at
	 */
	const CS_CONSTRUCTED=0;
	const CS_CHILD_INITIALIZED=1;
	const CS_INITIALIZED=2;
	const CS_STATE_LOADED=3;
	const CS_LOADED=4;
	const CS_PRERENDERED=5;

	/**
	 * State bits.
	 */
	const IS_ID_SET=0x01;
	const IS_DISABLE_VIEWSTATE=0x02;
	const IS_SKIN_APPLIED=0x04;
	const IS_STYLESHEET_APPLIED=0x08;
	const IS_DISABLE_THEMING=0x10;
	const IS_CHILD_CREATED=0x20;
	const IS_CREATING_CHILD=0x40;

	/**
	 * Indexes for the rare fields.
	 * In order to save memory, rare fields will only be created if they are needed.
	 */
	const RF_CONTROLS=0;			// child controls
	const RF_CHILD_STATE=1;			// child state field
	const RF_NAMED_CONTROLS=2;		// list of controls whose namingcontainer is this control
	const RF_NAMED_CONTROLS_ID=3;	// counter for automatic id
	const RF_SKIN_ID=4;				// skin ID
	const RF_DATA_BINDINGS=5;		// data bindings
	const RF_EVENTS=6;				// event handlers
	const RF_CONTROLSTATE=7;		// controlstate
	const RF_NAMED_OBJECTS=8;		// controls declared with ID on template
	const RF_ADAPTER=9;				// adapter
	const RF_AUTO_BINDINGS=10;		// auto data bindings

	/**
	 * @var string control ID
	 */
	private $_id='';
	/**
	 * @var string control unique ID
	 */
	private $_uid;
	/**
	 * @var TControl parent of the control
	 */
	private $_parent;
	/**
	 * @var TPage page that the control resides in
	 */
	private $_page;
	/**
	 * @var TControl naming container of the control
	 */
	private $_namingContainer;
	/**
	 * @var TTemplateControl control whose template contains the control
	 */
	private $_tplControl;
	/**
	 * @var array viewstate data
	 */
	private $_viewState=array();
	/**
	 * @var array temporary state (usually set in template)
	 */
	private $_tempState=array();
	/**
	 * @var boolean whether we should keep state in viewstate
	 */
	private $_trackViewState=true;
	/**
	 * @var integer the current stage of the control lifecycles
	 */
	private $_stage=0;
	/**
	 * @var integer representation of the state bits
	 */
	private $_flags=0;
	/**
	 * @var array a collection of rare control data
	 */
	private $_rf=array();

	/**
	 * Returns a property value by name or a control by ID.
	 * This overrides the parent implementation by allowing accessing
	 * a control via its ID using the following syntax,
	 * <code>
	 * $menuBar=$this->menuBar;
	 * </code>
	 * Note, the control must be configured in the template
	 * with explicit ID. If the name matches both a property and a control ID,
	 * the control ID will take the precedence.
	 *
	 * @param string the property name or control ID
	 * @return mixed the property value or the target control
	 * @throws TInvalidOperationException if the property is not defined.
	 * @see registerObject
	 */
	public function __get($name)
	{
		if(isset($this->_rf[self::RF_NAMED_OBJECTS][$name]))
			return $this->_rf[self::RF_NAMED_OBJECTS][$name];
		else
			return parent::__get($name);
	}

	/**
	 * @return boolean whether there is an adapter for this control
	 */
	public function getHasAdapter()
	{
		return isset($this->_rf[self::RF_ADAPTER]);
	}

	/**
	 * @return TControlAdapter control adapter. Null if not exists.
	 */
	public function getAdapter()
	{
		return isset($this->_rf[self::RF_ADAPTER])?$this->_rf[self::RF_ADAPTER]:null;
	}

	/**
	 * @param TControlAdapter control adapter
	 */
	public function setAdapter(TControlAdapter $adapter)
	{
		$this->_rf[self::RF_ADAPTER]=$adapter;
	}

	/**
	 * @return TControl the parent of this control
	 */
	public function getParent()
	{
		return $this->_parent;
	}

	/**
	 * @return TControl the naming container of this control
	 */
	public function getNamingContainer()
	{
		if(!$this->_namingContainer && $this->_parent)
		{
			if($this->_parent instanceof INamingContainer)
				$this->_namingContainer=$this->_parent;
			else
				$this->_namingContainer=$this->_parent->getNamingContainer();
		}
		return $this->_namingContainer;
	}

	/**
	 * @return TPage the page that contains this control
	 */
	public function getPage()
	{
		if(!$this->_page)
		{
			if($this->_parent)
				$this->_page=$this->_parent->getPage();
			else if($this->_tplControl)
				$this->_page=$this->_tplControl->getPage();
		}
		return $this->_page;
	}

	/**
	 * Sets the page for a control.
	 * Only framework developers should use this method.
	 * @param TPage the page that contains this control
	 */
	public function setPage($page)
	{
		$this->_page=$page;
	}

	/**
	 * Sets the control whose template contains this control.
	 * Only framework developers should use this method.
	 * @param TTemplateControl the control whose template contains this control
	 */
	public function setTemplateControl($control)
	{
		$this->_tplControl=$control;
	}

	/**
	 * @return TTemplateControl the control whose template contains this control
	 */
	public function getTemplateControl()
	{
		if(!$this->_tplControl && $this->_parent)
			$this->_tplControl=$this->_parent->getTemplateControl();
		return $this->_tplControl;
	}

	/**
	 * @return TTemplateControl the control whose template is loaded from
	 * some external storage, such as file, db, and whose template ultimately
	 * contains this control.
	 */
	public function getSourceTemplateControl()
	{
		$control=$this;
		while(($control instanceof TControl) && ($control=$control->getTemplateControl())!==null)
		{
			if(($control instanceof TTemplateControl) && $control->getIsSourceTemplateControl())
				return $control;
		}
		return $this->getPage();
	}

	/**
	 * Gets the lifecycle step the control is currently at.
	 * This method should only be used by control developers.
	 * @return integer the lifecycle step the control is currently at.
	 * The value can be CS_CONSTRUCTED, CS_CHILD_INITIALIZED, CS_INITIALIZED,
	 * CS_STATE_LOADED, CS_LOADED, CS_PRERENDERED.
	 */
	protected function getControlStage()
	{
		return $this->_stage;
	}

	/**
	 * Sets the lifecycle step the control is currently at.
	 * This method should only be used by control developers.
	 * @param integer the lifecycle step the control is currently at.
	 * Valid values include CS_CONSTRUCTED, CS_CHILD_INITIALIZED, CS_INITIALIZED,
	 * CS_STATE_LOADED, CS_LOADED, CS_PRERENDERED.
	 */
	protected function setControlStage($value)
	{
		$this->_stage=$value;
	}

	/**
	 * Returns the id of the control.
	 * Control ID can be either manually set or automatically generated.
	 * If $hideAutoID is true, automatically generated ID will be returned as an empty string.
	 * @param boolean whether to hide automatically generated ID
	 * @return string the ID of the control
	 */
	public function getID($hideAutoID=true)
	{
		if($hideAutoID)
			return ($this->_flags & self::IS_ID_SET) ? $this->_id : '';
		else
			return $this->_id;
	}

	/**
	 * @param string the new control ID. The value must consist of word characters [a-zA-Z0-9_] only
	 * @throws TInvalidDataValueException if ID is in a bad format
	 */
	public function setID($id)
	{
		if(!preg_match(self::ID_FORMAT,$id))
			throw new TInvalidDataValueException('control_id_invalid',get_class($this),$id);
		$this->_id=$id;
		$this->_flags |= self::IS_ID_SET;
		$this->clearCachedUniqueID($this instanceof INamingContainer);
		if($this->_namingContainer)
			$this->_namingContainer->clearNameTable();
	}

	/**
	 * Returns a unique ID that identifies the control in the page hierarchy.
	 * A unique ID is the contenation of all naming container controls' IDs and the control ID.
	 * These IDs are separated by '$' character.
	 * Control users should not rely on the specific format of UniqueID, however.
	 * @return string a unique ID that identifies the control in the page hierarchy
	 */
	public function getUniqueID()
	{
		if($this->_uid==='' || $this->_uid===null)	// need to build the UniqueID
		{
			$this->_uid='';  // set to not-null, so that clearCachedUniqueID() may take action
			if($namingContainer=$this->getNamingContainer())
			{
				if($this->getPage()===$namingContainer)
					return ($this->_uid=$this->_id);
				else if(($prefix=$namingContainer->getUniqueID())==='')
					return $this->_id;
				else
					return ($this->_uid=$prefix.self::ID_SEPARATOR.$this->_id);
			}
			else	// no naming container
				return $this->_id;
		}
		else
			return $this->_uid;
	}

	/**
	 * Sets input focus to this control.
	 */
	public function focus()
	{
		$this->getPage()->setFocus($this);
	}

	/**
	 * Returns the client ID of the control.
	 * The client ID can be used to uniquely identify
	 * the control in client-side scripts (such as JavaScript).
	 * Do not rely on the explicit format of the return ID.
	 * @return string the client ID of the control
	 */
	public function getClientID()
	{
		return strtr($this->getUniqueID(),self::ID_SEPARATOR,self::CLIENT_ID_SEPARATOR);
	}

	/**
	 * Converts a unique ID to a client ID.
	 * @param string the unique ID of a control
	 * @return string the client ID of the control
	 */
	public static function convertUniqueIdToClientId($uniqueID)
	{
		return strtr($uniqueID,self::ID_SEPARATOR,self::CLIENT_ID_SEPARATOR);
	}

	/**
	 * @return string the skin ID of this control, '' if not set
	 */
	public function getSkinID()
	{
		return isset($this->_rf[self::RF_SKIN_ID])?$this->_rf[self::RF_SKIN_ID]:'';
	}

	/**
	 * @param string the skin ID of this control
	 * @throws TInvalidOperationException if the SkinID is set in a stage later than PreInit, or if the skin is applied already.
	 */
	public function setSkinID($value)
	{
		if(($this->_flags & self::IS_SKIN_APPLIED) || $this->_stage>=self::CS_CHILD_INITIALIZED)
			throw new TInvalidOperationException('control_skinid_unchangeable',get_class($this));
		else
			$this->_rf[self::RF_SKIN_ID]=$value;
	}

	/**
	 * @param string the skin ID of this control
	 * @throws TInvalidOperationException if the SkinID is set in a stage later than PreInit, or if the skin is applied already.
	 */
	public function getIsSkinApplied()
	{
		return ($this->_flags & self::IS_SKIN_APPLIED);
	}

	/**
	 * @return boolean whether theming is enabled for this control.
	 * The theming is enabled if the control and all its parents have it enabled.
	 */
	public function getEnableTheming()
	{
		if($this->_flags & self::IS_DISABLE_THEMING)
			return false;
		else
			return $this->_parent?$this->_parent->getEnableTheming():true;
	}

	/**
	 * @param boolean whether to enable theming
	 * @throws TInvalidOperationException if this method is invoked after OnPreInit
	 */
	public function setEnableTheming($value)
	{
		if($this->_stage>=self::CS_CHILD_INITIALIZED)
			throw new TInvalidOperationException('control_enabletheming_unchangeable',get_class($this),$this->getUniqueID());
		else if(TPropertyValue::ensureBoolean($value))
			$this->_flags &= ~self::IS_DISABLE_THEMING;
		else
			$this->_flags |= self::IS_DISABLE_THEMING;
	}

	/**
	 * Returns custom data associated with this control.
	 * A control may be associated with some custom data for various purposes.
	 * For example, a button may be associated with a string to identify itself
	 * in a generic OnClick event handler.
	 * @return mixed custom data associated with this control. Defaults to null.
	 */
	public function getCustomData()
	{
		return $this->getViewState('CustomData',null);
	}

	/**
	 * Associates custom data with this control.
	 * Note, the custom data must be serializable and unserializable.
	 * @param mixed custom data
	 */
	public function setCustomData($value)
	{
		$this->setViewState('CustomData',$value,null);
	}

	/**
	 * @return boolean whether the control has child controls
	 */
	public function getHasControls()
	{
		return isset($this->_rf[self::RF_CONTROLS]) && $this->_rf[self::RF_CONTROLS]->getCount()>0;
	}

	/**
	 * @return TControlCollection the child control collection
	 */
	public function getControls()
	{
		if(!isset($this->_rf[self::RF_CONTROLS]))
			$this->_rf[self::RF_CONTROLS]=$this->createControlCollection();
		return $this->_rf[self::RF_CONTROLS];
	}

	/**
	 * Creates a control collection object that is to be used to hold child controls
	 * @return TControlCollection control collection
	 * @see getControls
	 */
	protected function createControlCollection()
	{
		return $this->getAllowChildControls()?new TControlCollection($this):new TEmptyControlCollection($this);
	}

	/**
	 * Checks if a control is visible.
	 * If parent check is required, then a control is visible only if the control
	 * and all its ancestors are visible.
	 * @param boolean whether the parents should also be checked if visible
	 * @return boolean whether the control is visible (default=true).
	 */
	public function getVisible($checkParents=true)
	{
		if($checkParents)
		{
			for($control=$this;$control;$control=$control->_parent)
				if(!$control->getVisible(false))
					return false;
			return true;
		}
		else
			return $this->getViewState('Visible',true);
	}

	/**
	 * @param boolean whether the control is visible
	 */
	public function setVisible($value)
	{
		$this->setViewState('Visible',TPropertyValue::ensureBoolean($value),true);
	}

	/**
	 * Returns a value indicating whether the control is enabled.
	 * A control is enabled if it allows client user interaction.
	 * If $checkParents is true, all parent controls will be checked,
	 * and unless they are all enabled, false will be returned.
	 * The property Enabled is mainly used for {@link TWebControl}
	 * derived controls.
	 * @param boolean whether the parents should also be checked enabled
	 * @return boolean whether the control is enabled.
	 */
	public function getEnabled($checkParents=false)
	{
		if($checkParents)
		{
			for($control=$this;$control;$control=$control->_parent)
				if(!$control->getViewState('Enabled',true))
					return false;
			return true;
		}
		else
			return $this->getViewState('Enabled',true);
	}

	/**
	 * @param boolean whether the control is to be enabled.
	 */
	public function setEnabled($value)
	{
		$this->setViewState('Enabled',TPropertyValue::ensureBoolean($value),true);
	}

	/**
	 * @return boolean whether the control has custom attributes
	 */
	public function getHasAttributes()
	{
		if($attributes=$this->getViewState('Attributes',null))
			return $attributes->getCount()>0;
		else
			return false;
	}

	/**
	 * Returns the list of custom attributes.
	 * Custom attributes are name-value pairs that may be rendered
	 * as HTML tags' attributes.
	 * @return TAttributeCollection the list of custom attributes
	 */
	public function getAttributes()
	{
		if($attributes=$this->getViewState('Attributes',null))
			return $attributes;
		else
		{
			$attributes=new TAttributeCollection;
			$this->setViewState('Attributes',$attributes,null);
			return $attributes;
		}
	}

	/**
	 * @return boolean whether the named attribute exists
	 */
	public function hasAttribute($name)
	{
		if($attributes=$this->getViewState('Attributes',null))
			return $attributes->contains($name);
		else
			return false;
	}

	/**
	 * @return string attribute value, null if attribute does not exist
	 */
	public function getAttribute($name)
	{
		if($attributes=$this->getViewState('Attributes',null))
			return $attributes->itemAt($name);
		else
			return null;
	}

	/**
	 * Sets a custom control attribute.
	 * @param string attribute name
	 * @param string value of the attribute
	 */
	public function setAttribute($name,$value)
	{
		$this->getAttributes()->add($name,$value);
	}

	/**
	 * Removes the named attribute.
	 * @param string the name of the attribute to be removed.
	 * @return string attribute value removed, null if attribute does not exist.
	 */
	public function removeAttribute($name)
	{
		if($attributes=$this->getViewState('Attributes',null))
			return $attributes->remove($name);
		else
			return null;
	}

	/**
	 * @return boolean whether viewstate is enabled
	 */
	public function getEnableViewState($checkParents=false)
	{
		if($checkParents)
		{
			for($control=$this;$control!==null;$control=$control->getParent())
				if($control->_flags & self::IS_DISABLE_VIEWSTATE)
					return false;
			return true;
		}
		else
			return !($this->_flags & self::IS_DISABLE_VIEWSTATE);
	}

	/**
	 * @param boolean set whether to enable viewstate
	 */
	public function setEnableViewState($value)
	{
		if(TPropertyValue::ensureBoolean($value))
			$this->_flags &= ~self::IS_DISABLE_VIEWSTATE;
		else
			$this->_flags |= self::IS_DISABLE_VIEWSTATE;
	}

	/**
	 * Returns a controlstate value.
	 *
	 * This function is mainly used in defining getter functions for control properties
	 * that must be kept in controlstate.
	 * @param string the name of the controlstate value to be returned
	 * @param mixed the default value. If $key is not found in controlstate, $defaultValue will be returned
	 * @return mixed the controlstate value corresponding to $key
	 */
	protected function getControlState($key,$defaultValue=null)
	{
		return isset($this->_rf[self::RF_CONTROLSTATE][$key])?$this->_rf[self::RF_CONTROLSTATE][$key]:$defaultValue;
	}

	/**
	 * Sets a controlstate value.
	 *
	 * This function is very useful in defining setter functions for control properties
	 * that must be kept in controlstate.
	 * Make sure that the controlstate value must be serializable and unserializable.
	 * @param string the name of the controlstate value
	 * @param mixed the controlstate value to be set
	 * @param mixed default value. If $value===$defaultValue, the item will be cleared from controlstate
	 */
	protected function setControlState($key,$value,$defaultValue=null)
	{
		if($value===$defaultValue)
			unset($this->_rf[self::RF_CONTROLSTATE][$key]);
		else
			$this->_rf[self::RF_CONTROLSTATE][$key]=$value;
	}

	/**
	 * Clears a controlstate value.
	 * @param string the name of the controlstate value to be cleared
	 */
	protected function clearControlState($key)
	{
		unset($this->_rf[self::RF_CONTROLSTATE][$key]);
	}

	/**
	 * Sets a value indicating whether we should keep data in viewstate.
	 * When it is false, data saved via setViewState() will not be persisted.
	 * By default, it is true, meaning data will be persisted across postbacks.
	 * @param boolean whether data should be persisted
	 */
	public function trackViewState($enabled)
	{
		$this->_trackViewState=TPropertyValue::ensureBoolean($enabled);
	}

	/**
	 * Returns a viewstate value.
	 *
	 * This function is very useful in defining getter functions for component properties
	 * that must be kept in viewstate.
	 * @param string the name of the viewstate value to be returned
	 * @param mixed the default value. If $key is not found in viewstate, $defaultValue will be returned
	 * @return mixed the viewstate value corresponding to $key
	 */
	public function getViewState($key,$defaultValue=null)
	{
		if(isset($this->_viewState[$key]))
			return $this->_viewState[$key]!==null?$this->_viewState[$key]:$defaultValue;
		else if(isset($this->_tempState[$key]))
		{
			if(is_object($this->_tempState[$key]) && $this->_trackViewState)
				$this->_viewState[$key]=$this->_tempState[$key];
			return $this->_tempState[$key];
		}
		else
			return $defaultValue;
	}

	/**
	 * Sets a viewstate value.
	 *
	 * This function is very useful in defining setter functions for control properties
	 * that must be kept in viewstate.
	 * Make sure that the viewstate value must be serializable and unserializable.
	 * @param string the name of the viewstate value
	 * @param mixed the viewstate value to be set
	 * @param mixed default value. If $value===$defaultValue, the item will be cleared from the viewstate.
	 */
	public function setViewState($key,$value,$defaultValue=null)
	{
		if($this->_trackViewState)
		{
			$this->_viewState[$key]=$value;
			unset($this->_tempState[$key]);
		}
		else
		{
			unset($this->_viewState[$key]);
			$this->_tempState[$key]=$value;
		}
	}

	/**
	 * Clears a viewstate value.
	 * @param string the name of the viewstate value to be cleared
	 */
	public function clearViewState($key)
	{
		unset($this->_viewState[$key]);
		unset($this->_tempState[$key]);
	}

	/**
	 * Sets up the binding between a property (or property path) and an expression.
	 * The context of the expression is the template control (or the control itself if it is a page).
	 * @param string the property name, or property path
	 * @param string the expression
	 */
	public function bindProperty($name,$expression)
	{
		$this->_rf[self::RF_DATA_BINDINGS][$name]=$expression;
	}

	/**
	 * Breaks the binding between a property (or property path) and an expression.
	 * @param string the property name (or property path)
	 */
	public function unbindProperty($name)
	{
		unset($this->_rf[self::RF_DATA_BINDINGS][$name]);
	}

	/**
	 * Sets up the binding between a property (or property path) and an expression.
	 * Unlike regular databinding, the expression bound by this method
	 * is automatically evaluated during {@link prerenderRecursive()}.
	 * The context of the expression is the template control (or the control itself if it is a page).
	 * @param string the property name, or property path
	 * @param string the expression
	 */
	public function autoBindProperty($name,$expression)
	{
		$this->_rf[self::RF_AUTO_BINDINGS][$name]=$expression;
	}

	/**
	 * Performs the databinding for this control.
	 */
	public function dataBind()
	{
		$this->dataBindProperties();
		$this->onDataBinding(null);
		$this->dataBindChildren();
	}

	/**
	 * Databinding properties of the control.
	 */
	protected function dataBindProperties()
	{
		Prado::trace("Data bind properties",'System.Web.UI.TControl');
		if(isset($this->_rf[self::RF_DATA_BINDINGS]))
		{
			if(($context=$this->getTemplateControl())===null)
				$context=$this;
			foreach($this->_rf[self::RF_DATA_BINDINGS] as $property=>$expression)
				$this->setSubProperty($property,$context->evaluateExpression($expression));
		}
	}

	/**
	 * Auto databinding properties of the control.
	 */
	protected function autoDataBindProperties()
	{
		if(isset($this->_rf[self::RF_AUTO_BINDINGS]))
		{
			if(($context=$this->getTemplateControl())===null)
				$context=$this;
			foreach($this->_rf[self::RF_AUTO_BINDINGS] as $property=>$expression)
				$this->setSubProperty($property,$context->evaluateExpression($expression));
		}
	}

	/**
	 * Databinding child controls.
	 */
	protected function dataBindChildren()
	{
		Prado::trace("dataBindChildren()",'System.Web.UI.TControl');
		if(isset($this->_rf[self::RF_CONTROLS]))
		{
			foreach($this->_rf[self::RF_CONTROLS] as $control)
				if($control instanceof IBindable)
					$control->dataBind();
		}
	}

	/**
	 * @return boolean whether child controls have been created
	 */
	final protected function getChildControlsCreated()
	{
		return ($this->_flags & self::IS_CHILD_CREATED)!==0;
	}

	/**
	 * Sets a value indicating whether child controls are created.
	 * If false, any existing child controls will be cleared up.
	 * @param boolean whether child controls are created
	 */
	final protected function setChildControlsCreated($value)
	{
		if($value)
			$this->_flags |= self::IS_CHILD_CREATED;
		else
		{
			if($this->getHasControls() && ($this->_flags & self::IS_CHILD_CREATED))
				$this->getControls()->clear();
			$this->_flags &= ~self::IS_CHILD_CREATED;
		}
	}

	/**
	 * Ensures child controls are created.
	 * If child controls are not created yet, this method will invoke
	 * {@link createChildControls} to create them.
	 */
	public function ensureChildControls()
	{
		if(!($this->_flags & self::IS_CHILD_CREATED) && !($this->_flags & self::IS_CREATING_CHILD))
		{
			try
			{
				$this->_flags |= self::IS_CREATING_CHILD;
				if(isset($this->_rf[self::RF_ADAPTER]))
					$this->_rf[self::RF_ADAPTER]->createChildControls();
				else
					$this->createChildControls();
				$this->_flags &= ~self::IS_CREATING_CHILD;
				$this->_flags |= self::IS_CHILD_CREATED;
			}
			catch(Exception $e)
			{
				$this->_flags &= ~self::IS_CREATING_CHILD;
				$this->_flags |= self::IS_CHILD_CREATED;
				throw $e;
			}
		}
	}

	/**
	 * Creates child controls.
	 * This method can be overriden for controls who want to have their controls.
	 * Do not call this method directly. Instead, call {@link ensureChildControls}
	 * to ensure child controls are created only once.
	 */
	public function createChildControls()
	{
	}

	/**
	 * Finds a control by ID path within the current naming container.
	 * The current naming container is either the control itself
	 * if it implements {@link INamingContainer} or the control's naming container.
	 * The ID path is an ID sequence separated by {@link TControl::ID_SEPARATOR}.
	 * For example, 'Repeater1.Item1.Button1' looks for a control with ID 'Button1'
	 * whose naming container is 'Item1' whose naming container is 'Repeater1'.
	 * @param string ID of the control to be looked up
	 * @return TControl|null the control found, null if not found
	 * @throws TInvalidDataValueException if a control's ID is found not unique within its naming container.
	 */
	public function findControl($id)
	{
		$id=strtr($id,'.',self::ID_SEPARATOR);
		$container=($this instanceof INamingContainer)?$this:$this->getNamingContainer();
		if(!$container || !$container->getHasControls())
			return null;
		if(!isset($container->_rf[self::RF_NAMED_CONTROLS]))
		{
			$container->_rf[self::RF_NAMED_CONTROLS]=array();
			$container->fillNameTable($container,$container->_rf[self::RF_CONTROLS]);
		}
		if(($pos=strpos($id,self::ID_SEPARATOR))===false)
			return isset($container->_rf[self::RF_NAMED_CONTROLS][$id])?$container->_rf[self::RF_NAMED_CONTROLS][$id]:null;
		else
		{
			$cid=substr($id,0,$pos);
			$sid=substr($id,$pos+1);
			if(isset($container->_rf[self::RF_NAMED_CONTROLS][$cid]))
				return $container->_rf[self::RF_NAMED_CONTROLS][$cid]->findControl($sid);
			else
				return null;
		}
	}

	/**
	 * Finds all child and grand-child controls that are of the specified type.
	 * @param string the class name
	 * @param boolean whether the type comparison is strict or not. If false, controls of the parent classes of the specified class will also be returned.
	 * @return array list of controls found
	 */
	public function findControlsByType($type,$strict=true)
	{
		$controls=array();
		if($this->getHasControls())
		{
			foreach($this->_rf[self::RF_CONTROLS] as $control)
			{
				if(is_object($control) && (get_class($control)===$type || (!$strict && ($control instanceof $type))))
					$controls[]=$control;
				if(($control instanceof TControl) && $control->getHasControls())
					$controls=array_merge($controls,$control->findControlsByType($type,$strict));
			}
		}
		return $controls;
	}

	/**
	 * Finds all child and grand-child controls with the specified ID.
	 * Note, this method is different from {@link findControl} in that
	 * it searches through all controls that have this control as the ancestor
	 * while {@link findcontrol} only searches through controls that have this
	 * control as the direct naming container.
	 * @param string the ID being looked for
	 * @return array list of controls found
	 */
	public function findControlsByID($id)
	{
		$controls=array();
		if($this->getHasControls())
		{
			foreach($this->_rf[self::RF_CONTROLS] as $control)
			{
				if($control instanceof TControl)
				{
					if($control->_id===$id)
						$controls[]=$control;
					$controls=array_merge($controls,$control->findControlsByID($id));
				}
			}
		}
		return $controls;
	}

	/**
	 * Resets the control as a naming container.
	 * Only framework developers should use this method.
	 */
	public function clearNamingContainer()
	{
		unset($this->_rf[self::RF_NAMED_CONTROLS_ID]);
		$this->clearNameTable();
	}

	/**
	 * Registers an object by a name.
	 * A registered object can be accessed like a public member variable.
	 * This method should only be used by framework and control developers.
	 * @param string name of the object
	 * @param object object to be declared
	 * @see __get
	 */
	public function registerObject($name,$object)
	{
		if(isset($this->_rf[self::RF_NAMED_OBJECTS][$name]))
			throw new TInvalidOperationException('control_object_reregistered',$name);
		$this->_rf[self::RF_NAMED_OBJECTS][$name]=$object;
	}

	/**
	 * Unregisters an object by name.
	 * @param string name of the object
	 * @see registerObject
	 */
	public function unregisterObject($name)
	{
		unset($this->_rf[self::RF_NAMED_OBJECTS][$name]);
	}

	/**
	 * @return boolean whether an object has been registered with the name
	 * @see registerObject
	 */
	public function isObjectRegistered($name)
	{
		return isset($this->_rf[self::RF_NAMED_OBJECTS][$name]);
	}

	/**
	 * @return boolean true if the child control has been initialized.
	 */
	public function getHasChildInitialized()
	{
		return $this->getControlStage() >= self::CS_CHILD_INITIALIZED;
	}

	/**
	 * @return boolean true if the onInit event has raised.
	 */
	public function getHasInitialized()
	{
		return $this->getControlStage() >= self::CS_INITIALIZED;
	}

	/**
	 * @return boolean true if the control has loaded post data.
	 */
	public function getHasLoadedPostData()
	{
		return $this->getControlStage() >= self::CS_STATE_LOADED;
	}

	/**
	 * @return boolean true if the onLoad event has raised.
	 */
	public function getHasLoaded()
	{
		return $this->getControlStage() >= self::CS_LOADED;
	}

	/**
	 * @return boolean true if onPreRender event has raised.
	 */
	public function getHasPreRendered()
	{
		return $this->getControlStage() >= self::CS_PRERENDERED;
	}

	/**
	 * Returns the named registered object.
	 * A component with explicit ID on a template will be registered to
	 * the template owner. This method allows you to obtain this component
	 * with the ID.
	 * @return mixed the named registered object. Null if object is not found.
	 */
	public function getRegisteredObject($name)
	{
		return isset($this->_rf[self::RF_NAMED_OBJECTS][$name])?$this->_rf[self::RF_NAMED_OBJECTS][$name]:null;
	}

	/**
	 * @return boolean whether body contents are allowed for this control. Defaults to true.
	 */
	public function getAllowChildControls()
	{
		return true;
	}

	/**
	 * Adds the object instantiated on a template to the child control collection.
	 * This method overrides the parent implementation.
	 * Only framework developers and control developers should use this method.
	 * @param string|TComponent text string or component parsed and instantiated in template
	 * @see createdOnTemplate
	 */
	public function addParsedObject($object)
	{
		$this->getControls()->add($object);
	}

	/**
	 * Clears up the child state data.
	 * After a control loads its state, those state that do not belong to
	 * any existing child controls are stored as child state.
	 * This method will remove these state.
	 * Only frameworker developers and control developers should use this method.
	 */
	final protected function clearChildState()
	{
		unset($this->_rf[self::RF_CHILD_STATE]);
	}

	/**
	 * @param TControl the potential ancestor control
	 * @return boolean if the control is a descendent (parent, parent of parent, etc.)
	 * of the specified control
	 */
	final protected function isDescendentOf($ancestor)
	{
		$control=$this;
		while($control!==$ancestor && $control->_parent)
			$control=$control->_parent;
		return $control===$ancestor;
	}

	/**
	 * Adds a control into the child collection of the control.
	 * Control lifecycles will be caught up during the addition.
	 * Only framework developers should use this method.
	 * @param TControl the new child control
	 */
	public function addedControl($control)
	{
		if($control->_parent)
			$control->_parent->getControls()->remove($control);
		$control->_parent=$this;
		$control->_page=$this->getPage();
		$namingContainer=($this instanceof INamingContainer)?$this:$this->_namingContainer;
		if($namingContainer)
		{
			$control->_namingContainer=$namingContainer;
			if($control->_id==='')
				$control->generateAutomaticID();
			else
				$namingContainer->clearNameTable();
			$control->clearCachedUniqueID($control instanceof INamingContainer);
		}

		if($this->_stage>=self::CS_CHILD_INITIALIZED)
		{
			$control->initRecursive($namingContainer);
			if($this->_stage>=self::CS_STATE_LOADED)
			{
				if(isset($this->_rf[self::RF_CHILD_STATE][$control->_id]))
				{
					$state=$this->_rf[self::RF_CHILD_STATE][$control->_id];
					unset($this->_rf[self::RF_CHILD_STATE][$control->_id]);
				}
				else
					$state=null;
				$control->loadStateRecursive($state,!($this->_flags & self::IS_DISABLE_VIEWSTATE));
				if($this->_stage>=self::CS_LOADED)
				{
					$control->loadRecursive();
					if($this->_stage>=self::CS_PRERENDERED)
						$control->preRenderRecursive();
				}
			}
		}
	}

	/**
	 * Removes a control from the child collection of the control.
	 * Only framework developers should use this method.
	 * @param TControl the child control removed
	 */
	public function removedControl($control)
	{
		if($this->_namingContainer)
			$this->_namingContainer->clearNameTable();
		$control->unloadRecursive();
		$control->_parent=null;
		$control->_page=null;
		$control->_namingContainer=null;
		$control->_tplControl=null;
		//$control->_stage=self::CS_CONSTRUCTED;
		if(!($control->_flags & self::IS_ID_SET))
			$control->_id='';
		else
			unset($this->_rf[self::RF_NAMED_OBJECTS][$control->_id]);
		$control->clearCachedUniqueID(true);
	}

	/**
	 * Performs the Init step for the control and all its child controls.
	 * Only framework developers should use this method.
	 * @param TControl the naming container control
	 */
	protected function initRecursive($namingContainer=null)
	{
		$this->ensureChildControls();
		if($this->getHasControls())
		{
			if($this instanceof INamingContainer)
				$namingContainer=$this;
			$page=$this->getPage();
			foreach($this->_rf[self::RF_CONTROLS] as $control)
			{
				if($control instanceof TControl)
				{
					$control->_namingContainer=$namingContainer;
					$control->_page=$page;
					if($control->_id==='' && $namingContainer)
						$control->generateAutomaticID();
					$control->initRecursive($namingContainer);
				}
			}
		}
		if($this->_stage<self::CS_INITIALIZED)
		{
			$this->_stage=self::CS_CHILD_INITIALIZED;
			if(($page=$this->getPage()) && $this->getEnableTheming() && !($this->_flags & self::IS_SKIN_APPLIED))
			{
				$page->applyControlSkin($this);
				$this->_flags |= self::IS_SKIN_APPLIED;
			}
			if(isset($this->_rf[self::RF_ADAPTER]))
				$this->_rf[self::RF_ADAPTER]->onInit(null);
			else
				$this->onInit(null);
			$this->_stage=self::CS_INITIALIZED;
		}
	}

	/**
	 * Performs the Load step for the control and all its child controls.
	 * Only framework developers should use this method.
	 */
	protected function loadRecursive()
	{
		if($this->_stage<self::CS_LOADED)
		{
			if(isset($this->_rf[self::RF_ADAPTER]))
				$this->_rf[self::RF_ADAPTER]->onLoad(null);
			else
				$this->onLoad(null);
		}
		if($this->getHasControls())
		{
			foreach($this->_rf[self::RF_CONTROLS] as $control)
			{
				if($control instanceof TControl)
					$control->loadRecursive();
			}
		}
		if($this->_stage<self::CS_LOADED)
			$this->_stage=self::CS_LOADED;
	}

	/**
	 * Performs the PreRender step for the control and all its child controls.
	 * Only framework developers should use this method.
	 */
	protected function preRenderRecursive()
	{
		$this->autoDataBindProperties();

		if($this->getVisible(false))
		{
			if(isset($this->_rf[self::RF_ADAPTER]))
				$this->_rf[self::RF_ADAPTER]->onPreRender(null);
			else
				$this->onPreRender(null);
			if($this->getHasControls())
			{
				foreach($this->_rf[self::RF_CONTROLS] as $control)
				{
					if($control instanceof TControl)
						$control->preRenderRecursive();
					else if($control instanceof TCompositeLiteral)
						$control->evaluateDynamicContent();
				}
			}
		}
		$this->_stage=self::CS_PRERENDERED;
	}

	/**
	 * Performs the Unload step for the control and all its child controls.
	 * Only framework developers should use this method.
	 */
	protected function unloadRecursive()
	{
		if(!($this->_flags & self::IS_ID_SET))
			$this->_id='';
		if($this->getHasControls())
		{
			foreach($this->_rf[self::RF_CONTROLS] as $control)
				if($control instanceof TControl)
					$control->unloadRecursive();
		}
		if(isset($this->_rf[self::RF_ADAPTER]))
			$this->_rf[self::RF_ADAPTER]->onUnload(null);
		else
			$this->onUnload(null);
	}

	/**
	 * This method is invoked when the control enters 'OnInit' stage.
	 * The method raises 'OnInit' event.
	 * If you override this method, be sure to call the parent implementation
	 * so that the event handlers can be invoked.
	 * @param TEventParameter event parameter to be passed to the event handlers
	 */
	public function onInit($param)
	{
		$this->raiseEvent('OnInit',$this,$param);
	}

	/**
	 * This method is invoked when the control enters 'OnLoad' stage.
	 * The method raises 'OnLoad' event.
	 * If you override this method, be sure to call the parent implementation
	 * so that the event handlers can be invoked.
	 * @param TEventParameter event parameter to be passed to the event handlers
	 */
	public function onLoad($param)
	{
		$this->raiseEvent('OnLoad',$this,$param);
	}

	/**
	 * Raises 'OnDataBinding' event.
	 * This method is invoked when {@link dataBind} is invoked.
	 * @param TEventParameter event parameter to be passed to the event handlers
	 */
	public function onDataBinding($param)
	{
		Prado::trace("onDataBinding()",'System.Web.UI.TControl');
		$this->raiseEvent('OnDataBinding',$this,$param);
	}


	/**
	 * This method is invoked when the control enters 'OnUnload' stage.
	 * The method raises 'OnUnload' event.
	 * If you override this method, be sure to call the parent implementation
	 * so that the event handlers can be invoked.
	 * @param TEventParameter event parameter to be passed to the event handlers
	 */
	public function onUnload($param)
	{
		$this->raiseEvent('OnUnload',$this,$param);
	}

	/**
	 * This method is invoked when the control enters 'OnPreRender' stage.
	 * The method raises 'OnPreRender' event.
	 * If you override this method, be sure to call the parent implementation
	 * so that the event handlers can be invoked.
	 * @param TEventParameter event parameter to be passed to the event handlers
	 */
	public function onPreRender($param)
	{
		$this->raiseEvent('OnPreRender',$this,$param);
	}

	/**
	 * Invokes the parent's bubbleEvent method.
	 * A control who wants to bubble an event must call this method in its onEvent method.
	 * @param TControl sender of the event
	 * @param TEventParameter event parameter
	 * @see bubbleEvent
	 */
	protected function raiseBubbleEvent($sender,$param)
	{
		$control=$this;
		while($control=$control->_parent)
		{
			if($control->bubbleEvent($sender,$param))
				break;
		}
	}

	/**
	 * This method responds to a bubbled event.
	 * This method should be overriden to provide customized response to a bubbled event.
	 * Check the type of event parameter to determine what event is bubbled currently.
	 * @param TControl sender of the event
	 * @param TEventParameter event parameters
	 * @return boolean true if the event bubbling is handled and no more bubbling.
	 * @see raiseBubbleEvent
	 */
	public function bubbleEvent($sender,$param)
	{
		return false;
	}

	/**
	 * Broadcasts an event.
	 * The event will be sent to all controls on the current page hierarchy.
	 * If a control defines the event, the event will be raised for the control.
	 * If a control implements {@link IBroadcastEventReceiver}, its
	 * {@link IBroadcastEventReceiver::broadcastEventReceived broadcastEventReceived()} method will
	 * be invoked which gives the control a chance to respond to the event.
	 * For example, when broadcasting event 'OnClick', all controls having 'OnClick'
	 * event will have this event raised, and all controls implementing
	 * {@link IBroadcastEventReceiver} will also have its
	 * {@link IBroadcastEventReceiver::broadcastEventReceived broadcastEventReceived()}
	 * invoked.
	 * @param string name of the broadcast event
	 * @param TControl sender of this event
	 * @param TEventParameter event parameter
	 */
	public function broadcastEvent($name,$sender,$param)
	{
		$rootControl=(($page=$this->getPage())===null)?$this:$page;
		$rootControl->broadcastEventInternal($name,$sender,new TBroadcastEventParameter($name,$param));
	}

	/**
	 * Recursively broadcasts an event.
	 * This method should only be used by framework developers.
	 * @param string name of the broadcast event
	 * @param TControl sender of the event
	 * @param TBroadcastEventParameter event parameter
	 */
	private function broadcastEventInternal($name,$sender,$param)
	{
		if($this->hasEvent($name))
			$this->raiseEvent($name,$sender,$param->getParameter());
		if($this instanceof IBroadcastEventReceiver)
			$this->broadcastEventReceived($sender,$param);
		if($this->getHasControls())
		{
			foreach($this->_rf[self::RF_CONTROLS] as $control)
			{
				if($control instanceof TControl)
					$control->broadcastEventInternal($name,$sender,$param);
			}
		}
	}

	/**
	 * Traverse the whole control hierarchy rooted at this control.
	 * Callback function may be invoked for each control being visited.
	 * A pre-callback is invoked before traversing child controls;
	 * A post-callback is invoked after traversing child controls.
	 * Callback functions can be global functions or class methods.
	 * They must be of the following signature:
	 * <code>
	 * function callback_func($control,$param) {...}
	 * </code>
	 * where $control refers to the control being visited and $param
	 * is the parameter that is passed originally when calling this traverse function.
	 *
	 * @param mixed parameter to be passed to callbacks for each control
	 * @param callback callback invoked before traversing child controls. If null, it is ignored.
	 * @param callback callback invoked after traversing child controls. If null, it is ignored.
	 */
	protected function traverseChildControls($param,$preCallback=null,$postCallback=null)
	{
		if($preCallback!==null)
			call_user_func($preCallback,$this,$param);
		if($this->getHasControls())
		{
			foreach($this->_rf[self::RF_CONTROLS] as $control)
			{
				if($control instanceof TControl)
				{
					$control->traverseChildControls($param,$preCallback,$postCallback);
				}
			}
		}
		if($postCallback!==null)
			call_user_func($postCallback,$this,$param);
	}

	/**
	 * Renders the control.
	 * Only when the control is visible will the control be rendered.
	 * @param THtmlWriter the writer used for the rendering purpose
	 */
	public function renderControl($writer)
	{
		if($this instanceof IActiveControl || $this->getVisible(false))
		{
			if(isset($this->_rf[self::RF_ADAPTER]))
				$this->_rf[self::RF_ADAPTER]->render($writer);
			else
				$this->render($writer);
		}
	}

	/**
	 * Renders the control.
	 * This method is invoked by {@link renderControl} when the control is visible.
	 * You can override this method to provide customized rendering of the control.
	 * By default, the control simply renders all its child contents.
	 * @param THtmlWriter the writer used for the rendering purpose
	 */
	public function render($writer)
	{
		$this->renderChildren($writer);
	}

	/**
	 * Renders the children of the control.
	 * This method iterates through all child controls and static text strings
	 * and renders them in order.
	 * @param THtmlWriter the writer used for the rendering purpose
	 */
	public function renderChildren($writer)
	{
		if($this->getHasControls())
		{
			foreach($this->_rf[self::RF_CONTROLS] as $control)
			{
				if(is_string($control))
					$writer->write($control);
				else if($control instanceof TControl)
					$control->renderControl($writer);
				else if($control instanceof IRenderable)
					$control->render($writer);
			}
		}
	}

	/**
	 * This method is invoked when control state is to be saved.
	 * You can override this method to do last step state saving.
	 * Parent implementation must be invoked.
	 */
	public function saveState()
	{
	}

	/**
	 * This method is invoked right after the control has loaded its state.
	 * You can override this method to initialize data from the control state.
	 * Parent implementation must be invoked.
	 */
	public function loadState()
	{
	}

	/**
	 * Loads state (viewstate and controlstate) into a control and its children.
	 * This method should only be used by framework developers.
	 * @param array the collection of the state
	 * @param boolean whether the viewstate should be loaded
	 */
	protected function loadStateRecursive(&$state,$needViewState=true)
	{
		if(is_array($state))
		{
			// A null state means the stateful properties all take default values.
			// So if the state is enabled, we have to assign the null value.
			$needViewState=($needViewState && !($this->_flags & self::IS_DISABLE_VIEWSTATE));
			if(isset($state[1]))
			{
				$this->_rf[self::RF_CONTROLSTATE]=&$state[1];
				unset($state[1]);
			}
			else
				unset($this->_rf[self::RF_CONTROLSTATE]);
			if($needViewState)
			{
				if(isset($state[0]))
					$this->_viewState=&$state[0];
				else
					$this->_viewState=array();
			}
			unset($state[0]);
			if($this->getHasControls())
			{
				foreach($this->_rf[self::RF_CONTROLS] as $control)
				{
					if($control instanceof TControl)
					{
						if(isset($state[$control->_id]))
						{
							$control->loadStateRecursive($state[$control->_id],$needViewState);
							unset($state[$control->_id]);
						}
					}
				}
			}
			if(!empty($state))
				$this->_rf[self::RF_CHILD_STATE]=&$state;
		}
		$this->_stage=self::CS_STATE_LOADED;
		if(isset($this->_rf[self::RF_ADAPTER]))
			$this->_rf[self::RF_ADAPTER]->loadState();
		else
			$this->loadState();
	}

	/**
	 * Saves all control state (viewstate and controlstate) as a collection.
	 * This method should only be used by framework developers.
	 * @param boolean whether the viewstate should be saved
	 * @return array the collection of the control state (including its children's state).
	 */
	protected function &saveStateRecursive($needViewState=true)
	{
		if(isset($this->_rf[self::RF_ADAPTER]))
			$this->_rf[self::RF_ADAPTER]->saveState();
		else
			$this->saveState();
		$needViewState=($needViewState && !($this->_flags & self::IS_DISABLE_VIEWSTATE));
		$state=array();
		if($this->getHasControls())
		{
			foreach($this->_rf[self::RF_CONTROLS] as $control)
			{
				if($control instanceof TControl)
					$state[$control->_id]=&$control->saveStateRecursive($needViewState);
			}
		}
		if($needViewState && !empty($this->_viewState))
			$state[0]=&$this->_viewState;
		if(isset($this->_rf[self::RF_CONTROLSTATE]))
			$state[1]=&$this->_rf[self::RF_CONTROLSTATE];
		return $state;
	}

	/**
	 * Applies a stylesheet skin to a control.
	 * @param TPage the page containing the control
	 * @throws TInvalidOperationException if the stylesheet skin is applied already
	 */
	public function applyStyleSheetSkin($page)
	{
		if($page && !($this->_flags & self::IS_STYLESHEET_APPLIED))
		{
			$page->applyControlStyleSheet($this);
			$this->_flags |= self::IS_STYLESHEET_APPLIED;
		}
		else if($this->_flags & self::IS_STYLESHEET_APPLIED)
			throw new TInvalidOperationException('control_stylesheet_applied',get_class($this));
	}

	/**
	 * Clears the cached UniqueID.
	 * If $recursive=true, all children's cached UniqueID will be cleared as well.
	 * @param boolean whether the clearing is recursive.
	 */
	private function clearCachedUniqueID($recursive)
	{
		if($recursive && $this->_uid!==null && isset($this->_rf[self::RF_CONTROLS]))
		{
			foreach($this->_rf[self::RF_CONTROLS] as $control)
				if($control instanceof TControl)
					$control->clearCachedUniqueID($recursive);
		}
		$this->_uid=null;
	}

	/**
	 * Generates an automatic ID for the control.
	 */
	private function generateAutomaticID()
	{
		$this->_flags &= ~self::IS_ID_SET;
		if(!isset($this->_namingContainer->_rf[self::RF_NAMED_CONTROLS_ID]))
			$this->_namingContainer->_rf[self::RF_NAMED_CONTROLS_ID]=0;
		$id=$this->_namingContainer->_rf[self::RF_NAMED_CONTROLS_ID]++;
		$this->_id=self::AUTOMATIC_ID_PREFIX . $id;
		$this->_namingContainer->clearNameTable();
	}

	/**
	 * Clears the list of the controls whose IDs are managed by the specified naming container.
	 */
	private function clearNameTable()
	{
		unset($this->_rf[self::RF_NAMED_CONTROLS]);
	}

	/**
	 * Updates the list of the controls whose IDs are managed by the specified naming container.
	 * @param TControl the naming container
	 * @param TControlCollection list of controls
	 * @throws TInvalidDataValueException if a control's ID is not unique within its naming container.
	 */
	private function fillNameTable($container,$controls)
	{
		foreach($controls as $control)
		{
			if($control instanceof TControl)
			{
				if($control->_id!=='')
				{
					if(isset($container->_rf[self::RF_NAMED_CONTROLS][$control->_id]))
						throw new TInvalidDataValueException('control_id_nonunique',get_class($control),$control->_id);
					else
						$container->_rf[self::RF_NAMED_CONTROLS][$control->_id]=$control;
				}
				if(!($control instanceof INamingContainer) && $control->getHasControls())
					$this->fillNameTable($container,$control->_rf[self::RF_CONTROLS]);
			}
		}
	}
}


/**
 * TControlCollection class
 *
 * TControlCollection implements a collection that enables
 * controls to maintain a list of their child controls.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
class TControlCollection extends TList
{
	/**
	 * the control that owns this collection.
	 * @var TControl
	 */
	private $_o;

	/**
	 * Constructor.
	 * @param TControl the control that owns this collection.
	 * @param boolean whether the list is read-only
	 */
	public function __construct(TControl $owner,$readOnly=false)
	{
		$this->_o=$owner;
		parent::__construct(null,$readOnly);
	}

	/**
	 * @return TControl the control that owns this collection.
	 */
	protected function getOwner()
	{
		return $this->_o;
	}

	/**
	 * Inserts an item at the specified position.
	 * This overrides the parent implementation by performing additional
	 * operations for each newly added child control.
	 * @param integer the speicified position.
	 * @param mixed new item
	 * @throws TInvalidDataTypeException if the item to be inserted is neither a string nor a TControl.
	 */
	public function insertAt($index,$item)
	{
		if($item instanceof TControl)
		{
			parent::insertAt($index,$item);
			$this->_o->addedControl($item);
		}
		else if(is_string($item) || ($item instanceof IRenderable))
			parent::insertAt($index,$item);
		else
			throw new TInvalidDataTypeException('controlcollection_control_required');
	}

	/**
	 * Removes an item at the specified position.
	 * This overrides the parent implementation by performing additional
	 * cleanup work when removing a child control.
	 * @param integer the index of the item to be removed.
	 * @return mixed the removed item.
	 */
	public function removeAt($index)
	{
		$item=parent::removeAt($index);
		if($item instanceof TControl)
			$this->_o->removedControl($item);
		return $item;
	}

	/**
	 * Overrides the parent implementation by invoking {@link TControl::clearNamingContainer}
	 */
	public function clear()
	{
		parent::clear();
		if($this->_o instanceof INamingContainer)
			$this->_o->clearNamingContainer();
	}
}

/**
 * TEmptyControlCollection class
 *
 * TEmptyControlCollection implements an empty control list that prohibits adding
 * controls to it. This is useful for controls that do not allow child controls.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
class TEmptyControlCollection extends TControlCollection
{
	/**
	 * Constructor.
	 * @param TControl the control that owns this collection.
	 */
	public function __construct(TControl $owner)
	{
		parent::__construct($owner,true);
	}

	/**
	 * Inserts an item at the specified position.
	 * This overrides the parent implementation by ignoring new addition.
	 * @param integer the speicified position.
	 * @param mixed new item
	 */
	public function insertAt($index,$item)
	{
		if(!is_string($item))  // string is possible if property tag is used. we simply ignore it in this case
			parent::insertAt($index,$item);  // this will generate an exception in parent implementation
	}
}

/**
 * INamingContainer interface.
 * INamingContainer marks a control as a naming container.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
interface INamingContainer
{
}

/**
 * IPostBackEventHandler interface
 *
 * If a control wants to respond to postback event, it must implement this interface.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
interface IPostBackEventHandler
{
	/**
	 * Raises postback event.
	 * The implementation of this function should raise appropriate event(s) (e.g. OnClick, OnCommand)
	 * indicating the component is responsible for the postback event.
	 * @param string the parameter associated with the postback event
	 */
	public function raisePostBackEvent($param);
}

/**
 * IPostBackDataHandler interface
 *
 * If a control wants to load post data, it must implement this interface.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
interface IPostBackDataHandler
{
	/**
	 * Loads user input data.
	 * The implementation of this function can use $values[$key] to get the user input
	 * data that are meant for the particular control.
	 * @param string the key that can be used to retrieve data from the input data collection
	 * @param array the input data collection
	 * @return boolean whether the data of the control has been changed
	 */
	public function loadPostData($key,$values);
	/**
	 * Raises postdata changed event.
	 * The implementation of this function should raise appropriate event(s) (e.g. OnTextChanged)
	 * indicating the control data is changed.
	 */
	public function raisePostDataChangedEvent();
	/**
	 * @return boolean whether postback causes the data change. Defaults to false for non-postback state.
	 */
	public function getDataChanged();
}


/**
 * IValidator interface
 *
 * If a control wants to validate user input, it must implement this interface.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
interface IValidator
{
	/**
	 * Validates certain data.
	 * The implementation of this function should validate certain data
	 * (e.g. data entered into TTextBox control).
	 * @return boolean whether the data passes the validation
	 */
	public function validate();
	/**
	 * @return boolean whether the previous {@link validate()} is successful.
	 */
	public function getIsValid();
	/**
	 * @param boolean whether the validator validates successfully
	 */
	public function setIsValid($value);
	/**
	 * @return string error message during last validate
	 */
	public function getErrorMessage();
	/**
	 * @param string error message for the validation
	 */
	public function setErrorMessage($value);
}


/**
 * IValidatable interface
 *
 * If a control wants to be validated by a validator, it must implement this interface.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
interface IValidatable
{
	/**
	 * @return mixed the value of the property to be validated.
	 */
	public function getValidationPropertyValue();
	/**
	 * @return boolean wether this control's validators validated successfully (must default to true)
	 */
	public function getIsValid();
	/**
	 * @return boolean wether this control's validators validated successfully
	 */
	public function setIsValid($value);
}

/**
 * IBroadcastEventReceiver interface
 *
 * If a control wants to check broadcast event, it must implement this interface.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
interface IBroadcastEventReceiver
{
	/**
	 * Handles broadcast event.
	 * This method is invoked automatically when an event is broadcasted.
	 * Within this method, you may check the event name given in
	 * the event parameter to determine  whether you should respond to
	 * this event.
	 * @param TControl sender of the event
	 * @param TBroadCastEventParameter event parameter
	 */
	public function broadcastEventReceived($sender,$param);
}

/**
 * ITheme interface.
 *
 * This interface must be implemented by theme.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
interface ITheme
{
	/**
	 * Applies this theme to the specified control.
	 * @param TControl the control to be applied with this theme
	 */
	public function applySkin($control);
}

/**
 * ITemplate interface
 *
 * ITemplate specifies the interface for classes encapsulating
 * parsed template structures.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
interface ITemplate
{
	/**
	 * Instantiates the template.
	 * Content in the template will be instantiated as components and text strings
	 * and passed to the specified parent control.
	 * @param TControl the parent control
	 */
	public function instantiateIn($parent);
}

/**
 * IButtonControl interface
 *
 * IButtonControl specifies the common properties and events that must
 * be implemented by a button control, such as {@link TButton}, {@link TLinkButton},
 * {@link TImageButton}.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
interface IButtonControl
{
	/**
	 * @return string caption of the button
	 */
	public function getText();

	/**
	 * @param string caption of the button
	 */
	public function setText($value);

	/**
	 * @return boolean whether postback event trigger by this button will cause input validation
	 */
	public function getCausesValidation();

	/**
	 * @param boolean whether postback event trigger by this button will cause input validation
	 */
	public function setCausesValidation($value);

	/**
	 * @return string the command name associated with the {@link onCommand OnCommand} event.
	 */
	public function getCommandName();

	/**
	 * @param string the command name associated with the {@link onCommand OnCommand} event.
	 */
	public function setCommandName($value);

	/**
	 * @return string the parameter associated with the {@link onCommand OnCommand} event
	 */
	public function getCommandParameter();

	/**
	 * @param string the parameter associated with the {@link onCommand OnCommand} event.
	 */
	public function setCommandParameter($value);

	/**
	 * @return string the group of validators which the button causes validation upon postback
	 */
	public function getValidationGroup();

	/**
	 * @param string the group of validators which the button causes validation upon postback
	 */
	public function setValidationGroup($value);

	/**
	 * Raises <b>OnClick</b> event.
	 * @param TEventParameter event parameter to be passed to the event handlers
	 */
	public function onClick($param);

	/**
	 * Raises <b>OnCommand</b> event.
	 * @param TCommandEventParameter event parameter to be passed to the event handlers
	 */
	public function onCommand($param);

	/**
	 * @param boolean set by a panel to register this button as the default button for the panel.
	 */
	public function setIsDefaultButton($value);

	/**
	 * @return boolean true if this button is registered as a default button for a panel.
	 */
	public function getIsDefaultButton();
}

/**
 * ISurroundable interface
 *
 * Identifies controls that may create an additional surrounding tag. The id of the
 * tag can be obtained with {@link getSurroundingTagID}.
 *
 * @package System.Web.UI
 * @since 3.1.2
 */
interface ISurroundable
{
	/**
	 * @return string the id of the embedding tag of the control or the control's clientID if not surrounded
	 */
	public function getSurroundingTagID();
}

/**
 * TBroadcastEventParameter class
 *
 * TBroadcastEventParameter encapsulates the parameter data for
 * events that are broadcasted. The name of of the event is specified via
 * {@link setName Name} property while the event parameter is via
 * {@link setParameter Parameter} property.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
class TBroadcastEventParameter extends TEventParameter
{
	private $_name;
	private $_param;

	/**
	 * Constructor.
	 * @param string name of the broadcast event
	 * @param mixed parameter of the broadcast event
	 */
	public function __construct($name='',$parameter=null)
	{
		$this->_name=$name;
		$this->_param=$parameter;
	}

	/**
	 * @return string name of the broadcast event
	 */
	public function getName()
	{
		return $this->_name;
	}

	/**
	 * @param string name of the broadcast event
	 */
	public function setName($value)
	{
		$this->_name=$value;
	}

	/**
	 * @return mixed parameter of the broadcast event
	 */
	public function getParameter()
	{
		return $this->_param;
	}

	/**
	 * @param mixed parameter of the broadcast event
	 */
	public function setParameter($value)
	{
		$this->_param=$value;
	}
}

/**
 * TCommandEventParameter class
 *
 * TCommandEventParameter encapsulates the parameter data for <b>Command</b>
 * event of button controls. You can access the name of the command via
 * {@link getCommandName CommandName} property, and the parameter carried
 * with the command via {@link getCommandParameter CommandParameter} property.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
class TCommandEventParameter extends TEventParameter
{
	private $_name;
	private $_param;

	/**
	 * Constructor.
	 * @param string name of the command
	 * @param string parameter of the command
	 */
	public function __construct($name='',$parameter='')
	{
		$this->_name=$name;
		$this->_param=$parameter;
	}

	/**
	 * @return string name of the command
	 */
	public function getCommandName()
	{
		return $this->_name;
	}

	/**
	 * @return string parameter of the command
	 */
	public function getCommandParameter()
	{
		return $this->_param;
	}
}


/**
 * TCompositeLiteral class
 *
 * TCompositeLiteral is used internally by {@link TTemplate} for representing
 * consecutive static strings, expressions and statements.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Web.UI
 * @since 3.0
 */
class TCompositeLiteral extends TComponent implements IRenderable, IBindable
{
	const TYPE_EXPRESSION=0;
	const TYPE_STATEMENTS=1;
	const TYPE_DATABINDING=2;
	private $_container=null;
	private $_items=array();
	private $_expressions=array();
	private $_statements=array();
	private $_bindings=array();

	/**
	 * Constructor.
	 * @param array list of items to be represented by TCompositeLiteral
	 */
	public function __construct($items)
	{
		$this->_items=array();
		$this->_expressions=array();
		$this->_statements=array();
		foreach($items as $id=>$item)
		{
			if(is_array($item))
			{
				if($item[0]===self::TYPE_EXPRESSION)
					$this->_expressions[$id]=$item[1];
				else if($item[0]===self::TYPE_STATEMENTS)
					$this->_statements[$id]=$item[1];
				else if($item[0]===self::TYPE_DATABINDING)
					$this->_bindings[$id]=$item[1];
				$this->_items[$id]='';
			}
			else
				$this->_items[$id]=$item;
		}
	}

	/**
	 * @return TComponent container of this component. It serves as the evaluation context of expressions and statements.
	 */
	public function getContainer()
	{
		return $this->_container;
	}

	/**
	 * @param TComponent container of this component. It serves as the evaluation context of expressions and statements.
	 */
	public function setContainer(TComponent $value)
	{
		$this->_container=$value;
	}

	/**
	 * Evaluates the expressions and/or statements in the component.
	 */
	public function evaluateDynamicContent()
	{
		$context=$this->_container===null?$this:$this->_container;
		foreach($this->_expressions as $id=>$expression)
			$this->_items[$id]=$context->evaluateExpression($expression);
		foreach($this->_statements as $id=>$statement)
			$this->_items[$id]=$context->evaluateStatements($statement);
	}

	/**
	 * Performs databindings.
	 * This method is required by {@link IBindable}
	 */
	public function dataBind()
	{
		$context=$this->_container===null?$this:$this->_container;
		foreach($this->_bindings as $id=>$binding)
			$this->_items[$id]=$context->evaluateExpression($binding);
	}

	/**
	 * Renders the content stored in this component.
	 * This method is required by {@link IRenderable}
	 * @param ITextWriter
	 */
	public function render($writer)
	{
		$writer->write(implode('',$this->_items));
	}
}