受保护的覆盖无效OnKeyUp未被调用 [英] protected override void OnKeyUp not being called

问题描述

我正在尝试捕获键入事件.由于某些原因，在C#中无法使用常规的KeyUp事件处理程序.我要执行的操作是在抬起Alt键时运行一些代码.我尝试使用此:

I am attempting to catch a keyup event. For some reason using the regular KeyUp event handler is not working in C#. What I am wanting to do is run some code when the Alt key is lifted. I tried using this:

protected override void OnKeyUp(KeyEventArgs e)<br />
{<br />
    base.OnKeyUp(e);<br />
}<br />

并在base.OnKeyUp(e)的行上放置一个断点，无论按下什么，调试器都不会停在那里.我还尝试对我可以找到的每个关键事件使用替代.唯一成功的方法是ProcessDialogKey，但在keyData下给出的唯一信息是RButton |. Shift键| Alt并没有指示它是KeyDown还是KeyUp，而且我甚至不确定它是否适用于KeyUp.有什么建议吗?

我用以下方法在ProcessDialogKey上做了进一步的测试:

and placed a break point on the line of base.OnKeyUp(e) and no matter what was pressed the debugger wouldn''t stop there. I have also attempted using an override for about every key event I could find. The only one that had any success was ProcessDialogKey but the only information it gave under keyData was RButton | Shiftkey | Alt which gives no indication whether it was a KeyDown or KeyUp, and I''m not even sure it would work for KeyUp. Any suggestions?

I did further testing on ProcessDialogKey with this:

int x = 0;<br />
protected override bool ProcessDialogKey(Keys keyData)<br />
{<br />
    if (keyData.ToString().Contains("Alt") == true && x == 0)<br />
        x += 1;<br />
    else<br />
x = 2;<br />
    return base.ProcessDialogKey(keyData);<br />
}<br />

并将断点放在x = 2的行上，以尝试查看这是否适用于KeyUp和KeyDown.调试器没有在KeyUp事件的这一行停止，而是在我第二次按Alt键时停止了.

and placed the break point on the line of x = 2 to attempt to see if this worked for KeyUp and KeyDown. The debugger did not stop at this line for the KeyUp event but did stop the second time I pushed the Alt key.

推荐答案

您是否尝试添加myForm.KeyPreview = true;

由于Alt用于某些与系统相关的事情，因此有时会出现问题，并且其处理方式与普通键有所不同. 请参阅此处 [

Since Alt is used for some system related things, it sometimes gives problems and has to be handled somewhat differently than normal keys. See here[^]

检查键事件是否似乎被路由到另一个控件.

Check if the key event appears to be getting routed to another control.

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