Crash in OnLostKeyboardFocus

[sycsoft]

In all place where you used "managedCefBrowserAdapter", you need do check like below:
if (!(managedCefBrowserAdapter != null && !managedCefBrowserAdapter.IsDisposed))
return;
This is because, in WPF, if I put the UI in a another thread, the event will still happen after disposed, so "managedCefBrowserAdapter" will become null or disposed.
private void OnLostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
managedCefBrowserAdapter.SendFocusEvent(false);
}

[sycsoft]

Sorry to add, it is in CefSharp.Wpf project.

[amaitland]

@sycsoft Can you clarify what you mean by the following?

This is because, in WPF, if I put the UI in a another thread, the event will still happen after disposed, so "managedCefBrowserAdapter" will become null or disposed.

Just a little nitpick, the code you provided as an example can be simplified as

if (managedCefBrowserAdapter == null || managedCefBrowserAdapter.IsDisposed))
    return;

[amaitland]

Possibly even provide a sample demonstrating the problem your having? Under a typical WPF usage scenario e.g. MVVM based UI the current implementation works as expected.

[sycsoft]

I tried, but unfortunately, I put this control into a complex WPF UI framework, I cannot reproduce it in simple demo, maybe I did not catch the point where it happens, but anyway I fix it by invoke Keyboard.ClearFocus() before dispose the browser, thanks.

[amaitland]

@sycsoft Can you apply this change locally and see if that resolves your problem in a generic sense?

amaitland@edf100c

I'd happily see the events unhooked when we start disposing the control.

[sycsoft]

I think I got the reason, seems when disposing, we dispose disposable objects then remove hook, but I checked "managedCefBrowserAdapter" will be disposed before remove hook, so this make it still possible to still send event before remove hook, I put the remove hook prior of clear disposable objects, it fixed my issue, but I am not sure if it will cause other issue, I think you will take care of this:).
protected virtual void Dispose(bool isdisposing)
{
Cef.RemoveDisposable(this);

        RemoveSourceHook(); //New place

        foreach (var disposable in disposables)
        {
            disposable.Dispose();
        }
        disposables.Clear();

        //RemoveSourceHook(); //Old place

        DoInUi(() => WebBrowser = null);
        managedCefBrowserAdapter = null;
        ConsoleMessage = null;
        FrameLoadStart = null;
        FrameLoadEnd = null;
        LoadError = null;
    }

[amaitland]

Fix for this has been merged into master