How can I intercept WndProc messages of CefSharp.WinForms.ChromiumWebBrowser?

Question

In order to intercept the WndProc messages of the CefSharp.WinForms.ChromiumWebBrowser control I'm using a derived class so I can use Protected Overrides Sub WndProc(ByRef m As Message) .

I have two issues:

1. I'm not receiving all messages (eg WM_MOUSEWHEEL)
2. Clicking on the control causes a message with the value 528 (=0x210) rather than the expected 513 (= 0x201 = WM_LBUTTONDOWN).

Searching for answers I stumbled across the following SO answer ( https://stackoverflow.com/a/20489430/4247806 ) which offered an explanation and a solution, but it appears quite complicated for a task that shouldn't be that unusual. I also didn't get it working for my CEF version, (CEF 3.2454.1344.g2782fb8, Chromium 45.0.2454.101 and .net 4.5.1.).

Concrete questions would be:

1. Why aren't all messages "forwarded"?
2. Why is the "mouse button down message" (and others) different?

Help would, obviously, be great ;)

Answer 1

The answer you have linked to is basically correct, the default is to run the message loop in a different thread, which makes it difficult to receive messages. You can use a NativeWindow to hook the relevant process, see https://github.com/cefsharp/CefSharp/blob/cefsharp/47/CefSharp.WinForms.Example/ChromeWidgetMessageInterceptor.cs#L22 for an example. Download the source to see it in action.

The other option is to use the existing WinForms message loop, see https://github.com/cefsharp/CefSharp/commit/fe11f2eada542f49e4eef0feed9b2b0978446bbf#diff-f142d024925e73816b0fabd620d2f71d for an example (Download the source code and step through if you have trouble following which pieces need to be set).