Problem with delegate Syntax in C#

Question

I built a Testbox to learn something about threading in windows form applications. Silverlight and Java are providing the Dispatcher, which really helps when updating GUI El

Answer 1

For simple delegates like this you can use the Action<T> delegate (link to msdn) from the framework.

public void UpdateTestBox(string newText)
{
    if (InvokeRequired)
    {
        BeginInvoke(new Action<string>(UpdateTestBox), new object[] { newText });
        return;
    }
    tb_output.Text = newText;
}

That way you do not need to maintain your own delegate declarations.

Answer 2

In many cases like this, the simplest approach is to use a "captured variable" to pass state between the threads; this means you can keep the logic localised:

public void UpdateTestBox(string newText)
{
    BeginInvoke((MethodInvoker) delegate {
        tb_output.Text = newText;
    });        
}

The above is particularly useful if we expect it to be called on the worker thread (so little point checking InvokeRequired) - note that this is safe from either the UI or worker thread, and allows us to pass as much or as little state between the threads.