Dispatcher.CheckAccess Method

Determines whether the calling thread is the thread associated with this Dispatcher.

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

member CheckAccess : unit -> bool

Return Value

Type: System.Boolean
true if the calling thread is the thread associated with this Dispatcher; otherwise, false.

Only the Dispatcher that a DispatcherObject is created on may access the object. Use Invoke or BeginInvoke to access the object from a different thread.

CheckAccess can be called from any thread.

The difference between CheckAccess and VerifyAccess is CheckAccess returns a Boolean indicating whether the calling thread has access to the Dispatcher and VerifyAccess throws an exception.

The following example uses CheckAccess to determine whether a thread has access to a Button. The CheckAccess method on the Dispatcher associated with the Button is called to verify access to the thread. If the calling thread has access to the Dispatcher, the Button is updated by accessing the members of the Button; otherwise, a delegate, which accepts a Button as an argument, is placed onto the Dispatcher. The Dispatcher will delegate the work of updating the Button.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0

.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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