Active Controls (AJAX enabled Controls)

See the Introduction for a quick overview of the concept behind active controls (AJAX enabled controls). Most active controls have a property of ActiveControl and a sub-property ClientSide that provides many properties to customize the controls. The CallbackClient property of the TPage class provides many methods to update and alter the client-side content during a callback request. Active controls is reliant on a collection of javascript classes.

For a quick demo of active controls, try the TActiveButton control. See also the later part of the Currency Converter tutorial for a more in depth example.

* the tutorial for this control is not completed yet.

Standard Active Controls

• TActiveButton represents a click button on a Web page. It can be used to trigger a callback request.
• TActiveCheckBox represents a checkbox on a Web page. It can be used to collect two-state user input and can trigger a callback request.
• TActiveCustomValidator validates a particular control using a callback request.
• TActiveHyperLink represents a hyperlink on a Web page.
• * TActiveImage represents an image on a Web page.
• * TActiveImageButton represents a click button that has an image as the background. It is can be used to trigger a callback request.
• * TActiveLabel represents a label on a Web page. The label can be customized via various CSS attributes.
• * TActiveLinkButton represents a hyperlink that can perform a callback request.
• * TActiveMultiView represents a container for a group of TView controls, each of which is container for other controls. At any time, at most one TView is visible. It's the active counterpart of TMultiView.
• * TActivePanel represents a container for other controls on a Web page. In HTML, it is displayed as a <div> element. The panel's contents can be replaced during a callback request.
• TActivePager generates UI that allows users to interactively specify which page of data to be displayed in a data-bound control.
• * TActiveRadioButton represents a radiobutton on a Web page. It is mainly used in a group from which users make a choice. It can be used to perform a callback request.
• * TActiveTextBox represents a text input field on a Web page. It can collect single-line, multi-line or password text input from users. It can be used to perform a callback request.
• * TCallbackOptions callback options such as OnLoading client-side event handlers.

Active List Controls

• * TActiveCheckBoxList displays a list of checkboxes on a Web page and each checkbox can trigger a callback request.
• * TActiveDropDownList displays a dropdown list box that allows users to select a single option from a few prespecified ones. It can be used to perform a callback request.
• * TActiveListBox displays a list box that allows single or multiple selection. It can be used to perform a callback request.
• * TActiveRadioButtonList is similar to TActiveCheckBoxList in every aspect except that each TActiveRadioButtonList displays a group of radiobuttons. Each radio button can perform a callback request.

Active Data Controls

• * TActiveDataList is used to display or modify a list of data items. It is the active counterpart to the original TDataList control.
• * TActiveDataGrid displays data in a tabular format with rows and columns. It is the active counterpart to the original TDataGrid control.
• * TActiveRepeater displays its content defined in templates repeatedly based on the given data. It is the active counterpart to the original TRepeater control.

Extended Active Controls

• TAutoComplete extends TActiveTextBox to offer text completion suggestions.
• * TCallback a generic control that can perform callback requests.
• * TEventTriggeredCallback triggers a callback request based on HTML DOM events.
• * TInPlaceTextBox represents a label that can be edited by clicked.
• * TTimeTriggeredCallback triggers a callback request based on time elapsed.
• * TValueTriggeredCallback monitors (using a timer) an attribute of an HTML element and triggers a callback request when the attribute value changes.
• TDropContainer & TDraggable represents drag and drop containers. The former will make its child controls "draggable" while the latter will raise a callback when a draggable control is dropped on it.

Active Control Abilities

The following table shows the Active Controls that can trigger a callback event and whether the control will raise a PostBack event if Javascript was disabled on the client's browser.

Active Control Infrastructure Classes

The following classes provide the basic infrastructure classes required to realize the active controls.

• * TActiveControlAdapter tracks the viewstate values of the control and update differences of the client-side HTML element attributes.
• * TActiveListControlAdapter allows the adapted list controls to change the selections on the client-side during a callback request.
• * TActivePageAdapter process the page life-cycle for callback requests.
• * TBaseActiveControl common active control methods and options.
• * TCallbackClientScript methods to manipulate the client-side HTML elements, also includes methods to invoke javascript Effects on HTML elements.
• * TCallbackClientSide common client-side callback request options, and client-side event handlers.
• * TCallbackResponseAdapter HTTP response for callback requests.