DispatcherObject.VerifyAccess Method

Enforces that the calling thread has access to this DispatcherObject.

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

'Declaration
Public Sub VerifyAccess

ExceptionCondition
InvalidOperationException

the calling thread does not have access to this DispatcherObject.

Only the thread the Dispatcher was created on may access the DispatcherObject.

Any thread can check to see whether it has access to this DispatcherObject.

The difference between CheckAccess and VerifyAccess is that CheckAccess returns a Boolean that specifies whether the calling thread has access to this DispatcherObject and VerifyAccess throws an exception if the calling thread does not have access to the this DispatcherObject.

The following example uses VerifyAccess to determine whether a thread has access to the thread that a Button was created on. If the calling thread does not have access, an InvalidOperationException is thrown.

					' Check if this thread has access to this object.
					theButton.VerifyAccess()

					' Thread has access to the object, so update the UI.
					UpdateButtonUI(theButton)

.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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