Dispatcher.BeginInvoke Method (Delegate, DispatcherPriority, Object)
Updated: July 2008
Executes the specified delegate asynchronously with the specified arguments, at the specified priority, on the thread that the Dispatcher was created on.
Assembly: WindowsBase (in WindowsBase.dll)
public DispatcherOperation BeginInvoke( Delegate method, DispatcherPriority priority, params Object args )
- Type: System.Delegate
The delegate to a method that takes parameters specified in args, which is pushed onto the Dispatcher event queue.
- Type: System.Windows.Threading.DispatcherPriority
The priority, relative to the other pending operations in the Dispatcher event queue, the specified method is invoked.
- Type: System.Object
An array of objects to pass as arguments to the given method. Can be null.
Changing the DispatcherPriority of the delegate as it is pending execution in the event queue.
Removing the delegate from the event queue.
Waiting for the delegate to return.
Obtaining the value that the delegate returns after it is executed.
BeginInvoke is asynchronous; therefore, control returns immediately to the calling object after it is called.
In WPF, only the thread that created a DispatcherObject may access that object. For example, a background thread that is spun off from the main UI thread cannot update the contents of a Button that was created on the UI thread. In order for the background thread to access the Content property of the Button, the background thread must delegate the work to the Dispatcher associated with the UI thread. This is accomplished by using either Invoke or BeginInvoke. Invoke is synchronous and BeginInvoke is asynchronous. The operation is added to the event queue of the Dispatcher at the specified DispatcherPriority.
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.