1 files changed, 38 insertions, 2 deletions

diff --git a/demos/quickstart/protected/pages/chap2/KeyConcepts.page b/demos/quickstart/protected/pages/chap2/KeyConcepts.page
index 5352d1ff..701633c4 100644
--- a/demos/quickstart/protected/pages/chap2/KeyConcepts.page
+++ b/demos/quickstart/protected/pages/chap2/KeyConcepts.page
@@ -8,7 +8,7 @@ A component is an instance of <code>TComponent</code> or its child class. The ba
 

 <h3>Component Properties</h3>

 <p>

-A property can be viewed as a public variable describing a specific aspect of the component, such as the background color, the font size, etc. A property is defined by the existence of a getter and/or a setter method of a component class. For example, in <code>TControl</code>, we have

+A component property can be viewed as a public variable describing a specific aspect of the component, such as the background color, the font size, etc. A property is defined by the existence of a getter and/or a setter method in the component class. For example, in <code>TControl</code>, we have

 <pre class="source">

 class TControl extends TComponent {

     public function getID() {

@@ -22,16 +22,52 @@ class TControl extends TComponent {
 This defines a property named <code>ID</code>. Reading the property (e.g. <code>echo $component-&gt;ID;</code>) is equivalent to invoking the getter method (e.g. <code>echo $component-&gt;getID();</code>); and writing the property (e.g. <code>$component-&gt;ID='Button';</code>) is equivalent to invoking the setter method (e.g. <code>$component-&gt;setID('Button');</code>).

 </p>

 <p>

-A property is read-only if it only has a getter method and no setter method. Since PHP method names are case-insensitive, property names are also case-insensitive.

+A property is read-only if it has a getter method but no setter method. Since PHP method names are case-insensitive, property names are also case-insensitive. A component class inherits all its ancestor classes' properties.

 </p>

 

 <h3>Component Events</h3>

+<p>

+Component events are special properties that take method names as their values. Attaching (setting) a method to an event will hook up the method to the places at which the event is raised. Therefore, the behavior of a component can be modified in a way that may not be foreseen during the development of the component.

+</p>

+<p>

+A component event is defined by the existence of an <code>on</code>-method. For example, in <code>TButton</code>, we have

+<pre class="source">

+class TButton extends TWebControl {

+    public function onClick($param) {

+        ...

+    }

+}

+</pre>

+This defines an event named <code>Click</code>, and a handler can be attached to the event using one of the following ways,

+<pre class="source">

+$button-&gt;Click=$callback;

+$button-&gt;Click-&gt;add($callback);

+$button-&gt;Click[]=$callback;

+$button-&gt;attachEventHandler('Click',$callback);

+</pre>

+where <code>$callback</code> refers to a valid PHP callback (e.g. a function name, a class method <code>array($object,'method')</code>, etc.)

+</p>

 

 <h2>Controls</h2>

 <p>

 A control is an instance of class <code>TControl</code> or its subclass. A control is a component defined in addition with user interface. The base class <code>TControl</code> defines the parent-child relationship among controls which reflects the containment relationship among user interface elements.

 </p>

 

+<h3>Parent-Child Relationship</h3>

+<p>

+A parent control is in charge of the state transition of its child controls. The rendering result of the child controls are usually used to compose the parent control's presentation.

+</p>

+<p>

+The parent-child relationship is usually established by the framework via <a href="?page=chap2.Templates1">templates</a>. In code, you may explicitly specify a control as a child of another using the following method,

+<pre class="source">

+$parent->Controls->add($child);

+</pre>

+where the property <code>Controls</code> refers to the child control collection of the parent.

+</p>

+

 <h2>Pages</h2>

+<p>

+Pages are top-most controls that have no parent (you may consider application as their container though). The presentation of pages are directly displayed to end-users.

+</p>

 

 </com:TContent>
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