CODEWITHSUNDEEP
c#multithreadingasync-awaitinvoke
Slicky
Slicky

Reputation: 97

Application.Current.Dispatcher.Invoke() from within an action

i have a problem where I run part of my code using the Dispatcher class from Application.Current namespace. Then I want to construct a follow up operation using the ContinueWith method of the task returned by Dispatcher.Invoke().

In this particular case, the follow up operation needs to be run from within the UI thread aswell, so it needs to be wrapped in the Dispatcher.Invoke again. This is how I got it to work:

Action doSomeMoreStuff = () => { this.MoreStuff; }
Application.Current.Dispatcher.Invoke(() => this.DoStuff).ContinueWith(x => Application.Current.Dispatcher.Invoke(this.DoSomeMoreStuff));

I want to keep it generic however, and there might be situations where I don't want the follow up code to be run from within the UI thread. So I tried to encapsulate the follow up code itself:

Action doSomeMoreStuff = () => { Application.Current.Dispatcher.Invoke(this.MoreStuff); }
Application.Current.Dispatcher.Invoke(() => this.DoStuff).ContinueWith(x => this.DoSomeMoreStuff);

So as far as I understand this problem, I simply switched the position of the Application.Current.Dispatcher.Invoke() call. However, the second approach does not work, the code does not get called, and I have no idea why.

What am I not getting here?

Upvotes: 1

Views: 5221

Answers (1)

Slicky
Slicky

Reputation: 97

I managed to solve my problem, ditching the ContinueWith(). It works 

Action followUpAction = () => { };
Application.Current.Dispatcher.Invoke(
                async () =>
                    {
                        await this.DoStuff()

                        followUpAction();
                    });

Thanks for the helpful comments though.

Upvotes: 1

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