Dispatcher.Invoke Method (Delegate, TimeSpan, Object[])

Executes the specified delegate within the designated time span at the specified priority with the specified arguments synchronously on the thread the Dispatcher is associated with.

Namespace:  System.Windows.Threading
Assembly:  WindowsBase (in WindowsBase.dll)

member Invoke : 
        method:Delegate * 
        timeout:TimeSpan * 
        args:Object[] -> Object

Parameters

method
Type: System.Delegate

A delegate to a method that takes parameters specified in args, which is pushed onto the Dispatcher event queue.

timeout
Type: System.TimeSpan

The maximum amount of time to wait for the operation to complete.

args
Type: System.Object[]

An array of objects to pass as arguments to the given method. Can be a null reference (Nothing in Visual Basic).

Return Value

Type: System.Object
The return value from the delegate being invoked or a null reference (Nothing in Visual Basic) if the delegate has no return value.

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.

Invoke is a synchronous operation; therefore, control will not return to the calling object until after the callback returns.

.NET Framework

Supported in: 4.5, 4, 3.5 SP1, 3.0 SP2

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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