JavaScript alert method in WebView2 cause application crash

Question

I have a WPF project that using Webview2 control(Microsoft.Web.WebView2.Wpf) and .NET 6, I implement the "alert" javascript method like this:

        private void W_ScriptDialogOpening(object? sender, Microsoft.Web.WebView2.Core.CoreWebView2ScriptDialogOpeningEventArgs e)
        {
            switch (e.Kind)
            {
                case Microsoft.Web.WebView2.Core.CoreWebView2ScriptDialogKind.Alert:
                    MessageBox.Show(e.Message, "MyTitle", MessageBoxButton.OK, MessageBoxImage.Information);
                    break;
                case Microsoft.Web.WebView2.Core.CoreWebView2ScriptDialogKind.Confirm:
                    if (MessageBox.Show(e.Message, "MyTitle", MessageBoxButton.YesNo, MessageBoxImage.Question) == MessageBoxResult.Yes)
                        e.Accept();
                    break;
                default:
                    MessageBox.Show("Hi");
                    break;
            }
        }

And then I run this project and open a html page with only one button, this button running javascript:alert("OK")

When I click this button, MessageBox.Show executed, I can see the dialog.

The problem is, if you don't close the dialog, left the dialog keep showing, about 25 seconds later the application will crash without any message, how to fix it?

Answer 1

According to https://github.com/MicrosoftEdge/WebView2Feedback/issues/1966 (which is a different issue), try an experimental workaround:

private void CoreWebView2_ScriptDialogOpening( object? sender, CoreWebView2ScriptDialogOpeningEventArgs e )
{
    CoreWebView2Deferral d = e.GetDeferral();
            
    Dispatcher.BeginInvoke( ( ) => ShowDialog( e, d ) );
}

void ShowDialog( CoreWebView2ScriptDialogOpeningEventArgs e, CoreWebView2Deferral d )
{
    switch( e.Kind )
    {
    case CoreWebView2ScriptDialogKind.Alert:
        MessageBox.Show( e.Message, "MyTitle", MessageBoxButton.OK, MessageBoxImage.Information );
        break;
    case CoreWebView2ScriptDialogKind.Confirm:
        if( MessageBox.Show( e.Message, "MyTitle", MessageBoxButton.YesNo, MessageBoxImage.Question ) == MessageBoxResult.Yes )
        {
            e.Accept( );
        }
        break;
    default:
        MessageBox.Show( "Hi" );
        break;
    }

    d.Complete();
    webView.Focus();
}

If it works, it probably can be extended for other kinds of alerts. The flow can be simplified if the debugger is not detected.