Cannot convert lambda expression to type 'System.Delegate'

c# multithreading dispatcher
mpen picture mpen · Mar 3, 2012 · Viewed 53.7k times · Source

Neither of these work:

_uiDispatcher.Invoke(() => { });
_uiDispatcher.Invoke(delegate() { });

All I want to do is Invoke an inline method on my main UI thread. So I called this on the main thread:

_uiDispatcher = Dispatcher.CurrentDispatcher;

And now I want to execute some code on that thread from another thread. How do I do it? Am I using the wrong syntax?

Note that this is not a WPF application; I've referenced WindowsBase so I could get access to the Dispatcher class.

Answer

thecoop picture thecoop · Mar 3, 2012

The problem is that you aren't providing the exact type of delegate you want to invoke. Dispatcher.Invoke just takes a Delegate. Is it an Action<T>? If so, what is T? Is it a MethodInvoker? Action? What?

If your delegate takes no arguments and returns nothing, you can use Action or MethodInvoker. Try this:

_uiDispatcher.Invoke(new Action(() => { }));

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