Cannot prevent closing of a window if use async OnClosingHandler

I have code like this in my window class.

       {
            // in constructor
            this.Closing += OnStandardClosing;
        }

        private async void OnStandardClosing(object? sender, System.ComponentModel.CancelEventArgs e)
        {
            if(!await CheckMaybeSavingOnClose())
            {
                e.Cancel = true;
            }
        }

But my window closes before I am will be able to choose an option before closing.

I tried to switch to syncronous handling by blocking on task but this prevent the second window from interactivity. The other thing I tried is adding Task type to OnStandardClosing but this doesn’t compile.

[kekekeks]

async void is essentially

task.ContinueWith(_ => <rest of you code>);
return;

so your OnStandardClosing returns immediately.

You need to cancel the close right away and close the window manually if CheckMaybeSavingOnClose returns true

[cristinathoughtpennies]

Nevermind, figured it out! I needed to remove the function call from Closing, this helped me: https://stackoverflow.com/questions/49012892/cannot-use-async-in-closing-method