DispatcherObject.CheckAccess DispatcherObject.CheckAccess DispatcherObject.CheckAccess DispatcherObject.CheckAccess Method

Definición

Determina si el subproceso de llamada tiene acceso a este DispatcherObject.Determines whether the calling thread has access to this DispatcherObject.

public:
 bool CheckAccess();
public bool CheckAccess ();
member this.CheckAccess : unit -> bool
Public Function CheckAccess () As Boolean

Devoluciones

true Si el subproceso que realiza la llamada tiene acceso a este objeto; en caso contrario, false.true if the calling thread has access to this object; otherwise, false.

Ejemplos

En el ejemplo siguiente se usa CheckAccess para determinar si un subproceso tiene acceso al subproceso que un Button se creó.The following example uses CheckAccess to determine whether a thread has access to the thread that a Button was created on. El CheckAccess método en el Button se llama para comprobar el acceso al subproceso.The CheckAccess method on the Button is called to verify access to the thread. Si el subproceso de llamada tiene acceso, el Button se actualiza mediante el acceso solo a los miembros de la Button; en caso contrario, un delegado, que acepta un Button como argumento, se registra en el Dispatcher de la Button.If the calling thread has access, the Button is updated by just accessing the members of the Button; otherwise, a delegate, which accepts a Button as an argument, is posted onto the Dispatcher of the Button.

// Uses the DispatcherObject.CheckAccess method to determine if 
// the calling thread has access to the thread the UI object is on
private void TryToUpdateButtonCheckAccess(object uiObject)
{
    Button theButton = uiObject as Button;

    if (theButton != null)
    {
        // Checking if this thread has access to the object
        if(theButton.CheckAccess())
        {
            // This thread has access so it can update the UI thread
            UpdateButtonUI(theButton);
        }
        else
        {
            // This thread does not have access to the UI thread
            // Pushing update method on the Dispatcher of the UI thread
            theButton.Dispatcher.BeginInvoke(DispatcherPriority.Normal,
                new UpdateUIDelegate(UpdateButtonUI), theButton);
        }
    }
}
' Uses the DispatcherObject.CheckAccess method to determine if 
' the calling thread has access to the thread the UI object is on
Private Sub TryToUpdateButtonCheckAccess(ByVal uiObject As Object)
	Dim theButton As Button = TryCast(uiObject, Button)

	If theButton IsNot Nothing Then
		' Checking if this thread has access to the object
		If theButton.CheckAccess() Then
			' This thread has access so it can update the UI thread
			UpdateButtonUI(theButton)
		Else
			' This thread does not have access to the UI thread
			' Pushing update method on the Dispatcher of the UI thread
			theButton.Dispatcher.BeginInvoke(DispatcherPriority.Normal, New UpdateUIDelegate(AddressOf UpdateButtonUI), theButton)
		End If
	End If
End Sub

Comentarios

Solo el subproceso de la Dispatcher se creó en pueden tener acceso a la DispatcherObject.Only the thread the Dispatcher was created on may access the DispatcherObject.

Cualquier subproceso puede comprobar para ver si tiene acceso a este DispatcherObject.Any thread can check to see whether it has access to this DispatcherObject.

La diferencia entre CheckAccess y VerifyAccess es que CheckAccess devuelve un valor booleano que especifica si el subproceso de llamada tiene acceso a este DispatcherObject y VerifyAccess produce una excepción si el subproceso de llamada no tiene acceso a la Esto 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.

Llamar a este método es idéntico a llamar a CheckAccess en asociado Dispatcher objeto.Calling this method is identical to calling CheckAccess on the associated Dispatcher object.

Se aplica a