WPF中的LeftAlt键绑定 [英] LeftAlt Keybinding in WPF

问题描述

我正在尝试将左ALT键与命令绑定在一起，以切换WPF中菜单的可见性. 但这不起作用..命令没有触发..

I'm trying to bind Left ALT key with a command to toggle visibility of a menu in WPF. But it doesn't work.. Command is not firing..

<Window.InputBindings>
        <KeyBinding
            Key="LeftAlt"
            Command="{Binding Path=MenuVisibilitySetCommand}"/>
</Window.InputBindings>

我注意到其他特殊键(例如Alt，Ctrl等)在这里也不起作用.

I've noticed that other special Keys ( such as Alt, Ctrl etc..) also not working here..

如何在WPF中对特殊键进行键绑定?

How to do KeyBinding for Special Key in WPF ?

推荐答案

这些特殊的键称为修饰符"键，这应该弄清楚为什么它不起作用.修饰键用于修改"给定键的行为，例如Shift + L表示大写字母"L"，而只有L表示小写字母"l".使用Modifierkeys进行实际逻辑操作可能会引起麻烦和烦躁，因为用户不习惯于按这些按钮时看到正在发生的实际动作.但是我同意在某些地方这是有意义的，例如按下ALT键时突出显示MenuItems.

These special Keys are called Modifier keys and this should make it clear why it is not working. A modifier Key is to "modify" the behavior of a given key, Like Shift + L makes an uppercase "L" where only the L key makes a lowercase "l". Using Modifierkeys for actual logic can be problematic and irritating, because the user is not accustomed to see real actions happening when pressing these kind of buttons. But i agree there are places where this makes sense e.g. highlighting MenuItems when hitting ALT key.

但是对于您的实际问题:您可以使用codebehind和OnKeyDown/OnKeyUp或Preview事件来实现此行为.

But to your actual problem: You could use codebehind and the OnKeyDown/OnKeyUp or the Preview events to implement this behavior.

    protected override void OnKeyDown(KeyEventArgs e)
    {
        if(e.SystemKey == Key.LeftAlt)
        {
            myMenu.Visibility = Visibility.Visible;
            // e.Handled = true; You need to evaluate if you really want to mark this key as handled!
        }

        base.OnKeyDown(e);
    }

当然，cou也可以在此代码中触发您的命令.

Of course cou could also fire your command in this code.

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