« Invoke CF and Full Fx | [again] Blog link of the week 40 »

Invoke with Whidbey

Fri, October 1, 2004, 05:30 AM under Whidbey | VisualStudio
Last time we looked at Control.Invoke on both CF and full framework. Assuming you have read it, let’s look at VS2005.

On the desktop, if you forget to use Control.Invoke, you now get an InvalidOperationException with the Message: "Illegal cross-thread operation: Control 'SomeControlName' accessed from a thread other than the thread it was created on." That is cool, and the stack trace will of course point you to the culprit. Note this only works when debugging in the IDE, and is not available to CF projects. Instead, with Smart Device projects, you get the (catchable) System.NotSupportedException (with the Beta 1 bits).

CF 2.0 brings parity with the desktop; all 3 limitations are removed, so you don't need the ThreadPool or the Queue or the need to cast: 


// ...or any other type/params you want

delegate void SomeCustomDelegate(object o);



// This method runs on a non-GUI thread e.g. Threading.Timer

internal void OnNonGuiThread(Object o){

    // if you have more than one argument just add it to the array

    object[] arr = {o};



    // assuming all this code is in a form

    this.BeginInvoke(new SomeCustomDelegate(UpdateBox), arr);

}



// This method runs on GUI thread

private void UpdateBox(Object o 

             /*other arguments as defined by SomeCustomDelegate*/){



    // TODO use o and other arguments

    this.Text = o.ToString();

}

Comments [0] |#Permalink
Comments are closed.