Public Overrides Function GetCallbackResult() As String

Visual Basic (Usage)	Copy Code
Dim instance As FloatingPanelTask Dim value As String   value = instance.GetCallbackResult()

public override string GetCallbackResult()

Return Value

GetCallbackResult is a method required when using client callbacks (i.e., when the class implements ICallbackEventHandler). It returns a string to the browser, which the browser then processes to update content or provide interaction with the user.

This version of GetCallbackResult:

1. Displays an activity indicator in the browser within the TaskResults that is buddied to the task, by calling the protected StartTaskActivityIndicator method;

2. Calls ExecuteTask to perform the task's work;

3. Calls the protected DisplayResults method to get the content required to update the task results on the client, and adds these results to the CallbackResults of the task; and

4. Returns the CallbackResults of the task as a string, which is passed to the client.

If you override GetCallbackResult, you should either call the base method to perform this work, or arrange to do the equivalent work in your own method.

A common reason to override GetCallbackResult is to store the _callbackArg values for later use. The user can right-click a result in TaskResults and choose to refresh or re-run the task. This option uses the Input object of the task, and assumes that the values used to execute the task are stored in Input. You can store the values from _callbackArg in Input to enable re-running the task. You should then access user input from Input within your ExecuteTask method, rather than from _callbackArg.

For discussion of callbacks in the Web ADF, see these references:

• The CallbackResult Class overview remarks.
• The topic Working with AJAX capabilities of the Web ADF in the Developer Help.

Target Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, Windows Vista, Windows Server 2008 family

Reference