wpf context menu left-click

Question

Is it possible to attach context menu to a wpf control and have it opened on left-click (as opposed to more customary right-click)? I want to achieve that using xaml only (this should be a part of my control's view template).

Solution 1

Here is a way to show context menu on left-click:

Create a new left button handler on the Border element:

<Border x:Name="Win"
        Width="40"
        Height="40"
        Background="Purple"
        MouseLeftButtonUp="UIElement_OnMouseLeftButtonUp">

and then add this:

private void UIElement_OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
    e.Handled = true;

    var mouseDownEvent =
        new MouseButtonEventArgs(Mouse.PrimaryDevice,
            Environment.TickCount,
            MouseButton.Right)
        {
            RoutedEvent = Mouse.MouseUpEvent,
            Source = Win,
        };


    InputManager.Current.ProcessInput(mouseDownEvent);
}

What it does, it basically maps the left-click into right-click. For reusability, you can wrap this into an attached behavior.

Solution 2

Here is how I would do a simple example of what I am suggesting:

The XAML:

<Window x:Class="LeftClickMenu.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow">
    <Grid>
        <Border Width="400" Height="300" Background="#ccc" BorderBrush="#333" 
                BorderThickness="1"
                MouseLeftButtonDown="Border_MouseLeftButtonDown"
                MouseRightButtonUp="Border_MouseRightButtonUp">
            <Border.ContextMenu>
                <ContextMenu x:Name="myContextMenu">
                    <MenuItem Header="Menu Item 1" />
                    <MenuItem Header="Menu Item 2" />
                    <MenuItem Header="Menu Item 3" />
                    <MenuItem Header="Menu Item 4" />
                    <MenuItem Header="Menu Item 5" />
                </ContextMenu>
            </Border.ContextMenu>
        </Border>
    </Grid>
</Window>

And the code-behind:

using System.Windows;
using System.Windows.Input;

namespace LeftClickMenu
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Border_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            myContextMenu.IsOpen = true;
        }

        private void Border_MouseRightButtonUp(object sender, MouseButtonEventArgs e)
        {
            e.Handled = true;
        }
    }
}

I also added the extra MouseRightButtonUp event to inhibit the right-click popup of the context menu.

Comments

[Tomasz Grobelny]

Wouldn't doing it from code violate the separation between view and logic? To me this part belongs to view (and so should be specified in xaml).

[Xcalibur37]

This is the code-behind of the view which is part of the view. What you are referring to would be in regard to implementing this code in a ViewModel and I am not suggesting that at all.

[Tomasz Grobelny]

Ok, so be it. But still, I do not understand the "Create an event for LeftMouseButtonDown and call that method" part. I have a style for my control inside Generic.xaml. I want the context menu to show up when I click on one of the controls defined in this style eg. Image control. So I tried to add MouseUp="method" to the Image tag, but I get: error MC4007: The event 'MouseUp' cannot be specified on a Target tag in a Style. Use an EventSetter instead. How do I wire up the event handler from within a style? Where should my method be located? Generic.xaml.cs?

[Xcalibur37]

I am putting a sample in a separate answer.

[Tomasz Grobelny]

(Sorry for late reply.) But how do I move this behaviour to style (eg. in Generic.xml). As indicated in my previous comment I get "error MC4007: The event 'MouseUp' cannot be specified on a Target tag in a Style. Use an EventSetter instead."

[Xcalibur37]

I agree with the error. You should use an Event setter. I don't believe there is an effective way to do that in a style since you need it to occur on a specific event.

[The Cookies Dog]

Thanks, this is the only solution I've found that respects what you specify in the ContextMenuService.Placement... properties.