How do you add access keys (shortcuts) to a WPF ContextMenu, programmatically?

问题

I already have the following:

var myContextMenu = new System.Windows.Controls.ContextMenu();

var exitItem = new MenuItem();
exitItem.Header = "E_xit";
exitItem.Item.Click += new RoutedEventHandler(new System.EventHandler(ExitProgram));
myContextMenu.Items.Add(exitItem);

This causes my context menu to display the Exit menu item, with an underlined "x". However, pressing x does nothing. Clicking the menu item works fine.

How can I associate an event with the x key? Please note that this has to be done programmatically in my context. I cannot compose this solution in the XAML in front.

回答1:

The usual way to add shortcuts is as follows:

var exitCommand = new RelayCommand(_ => ExitProgram());
        var exitItem = new MenuItem(); 
        exitItem.Header = "E_xit";
        exitItem.Command = exitCommand;
        myContextMenu.Items.Add(exitItem);

        InputBindings.Add(new KeyBinding(exitCommand, new KeyGesture(Key.X, ModifierKeys.Alt));

The RelayCommand class used here is not the part of WPF but it's widely used in MVVM-based apps.

Please note though, that you cannot set your shortcut to X without modifiers. Quote from MSDN

In most cases, a KeyGesture must be associated with one or more ModifierKeys. The exceptions to this rule are the function keys and the numeric keypad keys, which can be a valid KeyGesture by themselves. For example, you can create a KeyGesture by using only the F12 key, but to use the X key in a KeyGesture it must be paired with a modifier key.

If for some reason you need to use X w/o modifiers - you will have to handle keyboard events (eg KeyDown) and react accordingly

回答2:

This works fine for me:

using System.Windows;
using System.Windows.Controls;

namespace WpfApplication5
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            Loaded += new RoutedEventHandler(MainWindow_Loaded);
        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            // Create menu item.
            MenuItem exitMenuItem = new MenuItem();
            exitMenuItem.Header = "E_xit";
            exitMenuItem.Click +=new RoutedEventHandler(exitMenuItem_Click);

            // Create contextual menu.
            ContextMenu contextMenu = new ContextMenu();
            contextMenu.Items.Add(exitMenuItem);

            // Attach context-menu to something.
            myButton.ContextMenu = contextMenu; // Assuming there's a button on window named "myButton".
        }

        public void exitMenuItem_Click(object sender, RoutedEventArgs e)
        {
            // This gets executed when user right-clicks button, and presses x down on their keyboard.
            // TODO: Exit logic.
        }
    }
}


<Window x:Class="WpfApplication5.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow">
    <Grid>
        <Button x:Name="myButton" />
    </Grid>
</Window>

The exitMenuItem_Click handler gets executed when the user right-clicks the button and presses 'x' on their keyboard. Are you not seeing this happen?

来源：https://stackoverflow.com/questions/10981936/how-do-you-add-access-keys-shortcuts-to-a-wpf-contextmenu-programmatically

标签

wpf

shortcut