WPF: Add support for back and forward mouse buttons

[merceyz]

The WPF browser currently ignores XButton1 and XButton2.
These are used to navigate forward and backwards in Chrome, and should probably do so in CefSharp as well

CefSharp/CefSharp.Wpf/ChromiumWebBrowser.cs

Lines 2136 to 2140 in 244aab0

	// Cef currently only supports Left, Middle and Right button presses.
	if (e.ChangedButton > MouseButton.Right)
	{
	return;
	}

[frederikstonge]

Could it be possible to disable this feature? Add a boolean to disable these buttons or make the method overriable.

[fvanheeswijk]

It would be appreciated if this feature could be enabled/disabled at runtime, as most of the times this behaviour is wanted but sometimes it is not.

[amaitland]

You can already override the behavior, just inherit from ChromiumWebBrowser, override the two methods for mouse up/down and mark them as handled.

[fvanheeswijk]

@amaitland That should work indeed, thanks :) Though that does mean that I need to duplicate browser.GetHost().SendMouseClickEvent((int)point.X, (int)point.Y, (MouseButtonType)e.ChangedButton, mouseUp, e.ClickCount, modifiers);...

In short, if you change some things in private void OnMouseButton(MouseButtonEventArgs e) in the future, then I'll be missing those changes, I'm not sure if that is the best way to go, but for now it solves the issue.

[amaitland]

How about setting the eventargs as handled and call the base method? Shouldn't need to duplicate anything

[fvanheeswijk]

That means though that private void OnMouseButton(MouseButtonEventArgs e) will not execute anything anymore, right? As the guard is !e.Handled && browser != null. And I just notice that in protected override void OnMouseDown(MouseButtonEventArgs e) I need to duplicate the Focus() call too.

To clarify: I still want (most) of the original behavior of OnMouseUp and OnMouseDown, I just don't want the back/forward navigation using mouse buttons.

[amaitland]

To clarify: I still want (most) of the original behavior of OnMouseUp and OnMouseDown, I just don't want the back/forward navigation using mouse buttons.

That was perfectly clear.

And I just notice that in protected override void OnMouseDown(MouseButtonEventArgs e) I need to duplicate the Focus() call too.

For what reason?

CefSharp is build with GitLink, you can step into the source https://github.com/GitTools/GitLink

[fvanheeswijk]

I'll add the code of what I have thought of, hopefully you can see where I went wrong with this. I don't intend to use this in production as it is way too hacky. (I also haven't tested this code yet)

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;
using System.Xaml;
using System.Windows.Controls;
using System.Windows.Input;

using CefSharp;
using CefSharp.Wpf;
using CefSharp.Wpf.Internals;

namespace Redacted
{
    public class CustomChromiumWebBrowser : ChromiumWebBrowser
    {
        public bool IgnoreForwardBackMouseNavigation { get; private set; }

        protected override void OnMouseDown(MouseButtonEventArgs e)
        {
            if (IgnoreForwardBackMouseNavigation)
            {
                Focus();
                OnMouseButton(e);

                CallGrandBaseMethod("OnMouseDown", e);
            }
            else
            {
                base.OnMouseDown(e);
            }
        }

        protected override void OnMouseUp(MouseButtonEventArgs e)
        {
            if (IgnoreForwardBackMouseNavigation)
            {
                OnMouseButton(e);

                CallGrandBaseMethod("OnMouseUp", e);
            }
            else
            {
                base.OnMouseUp(e);
            }
        }

        private void OnMouseButton(MouseButtonEventArgs e)
        {
            // implementation copied from https://github.com/cefsharp/CefSharp/blob/cefsharp/63/CefSharp.Wpf/ChromiumWebBrowser.cs#L2123
            // we do not implement the back/forward mouse button functionality (via XButton1/XButton2)

            var browser = GetBrowser();

            if (!e.Handled && browser != null)
            {
                var modifiers = e.GetModifiers();
                var mouseUp = (e.ButtonState == MouseButtonState.Released);
                var point = e.GetPosition(this);

                browser.GetHost().SendMouseClickEvent((int)point.X, (int)point.Y, (MouseButtonType)e.ChangedButton, mouseUp, e.ClickCount, modifiers);

                e.Handled = true;
            }
        }

        private void CallGrandBaseMethod(string methodName, MouseButtonEventArgs e)
        {
            var pointer = typeof(ContentControl).GetMethod(methodName).MethodHandle.GetFunctionPointer();
            var grandBaseMethod = (Action<MouseButtonEventArgs>)Activator.CreateInstance(typeof(Action<MouseButtonEventArgs>, this, pointer);
            grandBaseMethod(e);
        }
    }
}

I could have gotten it to work in a reasonably nice way if base.base.method() was allowed, but I understand the reasons of why it is not allowed in C#. If private void OnMouseButton(MouseButtonEventArgs e) was protected then it would fix (most) of the issues too in this case.

[amaitland]

You appear to be overthinking things, try.

protected override void OnMouseDown(MouseButtonEventArgs e)
{
	if (e.ChangedButton == MouseButton.XButton1 || e.ChangedButton == MouseButton.XButton1)
	{
		e.Handled = true;
	}	

	base.OnMouseDown(e);
}

[fvanheeswijk]

That actually seems to be the solution I was looking for :) Thanks a lot, it is simple and effective.

[MelvilQ]

This is what we had to do to prevent navigation:

public class CustomChromiumWebBrowser : ChromiumWebBrowser
{
	protected override void OnMouseDown(MouseButtonEventArgs e)
	{
		if (e.ChangedButton == MouseButton.XButton1 || e.ChangedButton == MouseButton.XButton2)
		{
			e.Handled = true;
		}

		base.OnMouseDown(e);
	}

	protected override void OnMouseUp(MouseButtonEventArgs e)
	{
		if (e.ChangedButton == MouseButton.XButton1 || e.ChangedButton == MouseButton.XButton2)
		{
			e.Handled = true;
		}

		base.OnMouseUp(e);
	}
}