Issue when CEF is put inside listbox

[mohdimas]

There is a problem when we put cefsharp wpf control inside a listbox. It makes some keyboard shortcut such as ctrl+a not working.
I've pushed it here https://github.com/Bodekaer/CefSharp/tree/CefSharpInsideListBoxTest
Is there a workaround to fix this?

[mohdimas]

And to add more, performance when typing is noticeably slower.

[jankurianski]

Perhaps some shortcuts such as CTRL+A are handled by the listbox to select all items in a list?

Have you tried to put more items in the listbox and see if they get selected when you press CTRL+A?

Here is where you could start debugging to see whether the keyboard events are being captured by the WPF control : https://github.com/cefsharp/CefSharp/blob/master/CefSharp.Wpf/ChromiumWebBrowser.cs#L605-L630

[amaitland]

If you put a break point at https://github.com/cefsharp/CefSharp/blob/master/CefSharp.Wpf/ChromiumWebBrowser.cs#L894 in OnPreviewKey and another at https://github.com/cefsharp/CefSharp/blob/master/CefSharp.Wpf/ChromiumWebBrowser.cs#L620 in the SourceHook, you'll find out if WPF is handling the key combination.

OnPreviewKey will be first, and then the SourceHook, if only OnPreviewKey is fired then the event was handled elsewhere.

And to add more, performance when typing is noticeably slower.

Noticeably slower when compared to???

[mohdimas]

@amaitland
when typing between the cefsharp that is inside listbox, and the other which is not.

[amaitland]

when typing between the cefsharp that is inside listbox, and the other which is not.

At a guess if that's the case then it's likely that a total rewrite would be required, one that doesn't rely on a SourceHook.

Let us know how the debugging goes 👍

[amaitland]

@myrnazhou Any further feedback on this one?

[rassilon]

I haven't tried this, but does CEF send data back out for unhandled events through KeyboardHandler for OSR like we're using in WPF?

If it does, then that might be part of the solution. (I don't recall much about WPF keyboard event propigation.)

Additionally, it seems kind of odd to make the ListBoxItem be the WPF ChromiumWebBrowser. I would think you would rather write a wrapping WPF control that contains the ChromiumWebBrowser for the entire ListBox ControlTemplate. (or whatever the WPF term is, I haven't done a lot of WPF development at all.) That'd be a much better way of leveraging the amount of effort involved in starting up CEF.

(Especially,since the default list box style is to display more than one ListBoxItem at a time, IIRC.)

Bill

[mohdimas]

Sorry for the late reply,
So yes, apparently the Ctrl+A is not handled there, and if I added this condition to the OnPreviewKey, it solves the issue
(e.Key == Key.A && Keyboard.Modifiers == ModifierKeys.Control)

[amaitland]

Excellent. Anything else before closing this?

[mohdimas]

Should I make a PR?

[amaitland]

Yep, can you also include a comment as to the reason for the extra check?

[amaitland]

Closing as #883 has been merged.