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 Current Converter tutorial for a more indepth 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.
* 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.
* 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.

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.

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.

Control Name	Triggers Callback	Falls back to PostBack
TActiveButton	Yes	Yes
TActiveCheckBox	Yes	Yes
TActiveCustomValidator	Yes	Yes
TActiveHyperLink	No	Yes
TActiveImage	No	Yes
TActiveImageButton	Yes	Yes
TActiveLabel	No	Yes
TActiveLinkButton	Yes	No
TActivePanel	No	Yes
TActiveRadioButton	Yes	Yes
TActiveTextBox	Yes	Yes
TCallbackOptions	No	N/A
TActiveCheckBoxList	Yes	Yes
TActiveDropDownList	Yes	Yes
TActiveListBox	Yes	Yes
TActiveRadioButtonList	Yes	Yes
TAutoComplete	Yes	No
TCallback	Yes	No
TEventTriggeredCallback	Yes	No
TInPlaceTextBox	Yes	No
TTimeTriggeredCallback	Yes	No
TValueTriggeredCallback	Yes	No

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.

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