C# 和箭头键
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原文地址: http://stackoverflow.com/questions/4850/
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C# and Arrow Keys
提问by Redbaron
I am new to C# and am doing some work in an existing application. I have a DirectX viewport that has components in it that I want to be able to position using arrow keys.
我是 C# 新手，正在现有应用程序中做一些工作。我有一个 DirectX 视口，其中包含我希望能够使用箭头键定位的组件。
Currently I am overriding ProcessCmdKey and catching arrow input and send an OnKeyPress event. This works, but I want to be able to use modifiers(ALT+CTRL+SHIFT). As soon as I am holding a modifier and press an arrow no events are triggered that I am listening to.
目前我正在覆盖 ProcessCmdKey 并捕获箭头输入并发送 OnKeyPress 事件。这有效，但我希望能够使用修饰符（ALT+ CTRL+SHIFT）。只要我拿着修饰符并按下箭头，就不会触发我正在收听的事件。
Does anyone have any ideas or suggestions on where I should go with this?
有没有人对我应该去哪里有任何想法或建议？
采纳答案by Tokabi
Within your overridden ProcessCmdKey how are you determining which key has been pressed?
在您覆盖的 ProcessCmdKey 中，您如何确定按下了哪个键？
The value of keyData (the second parameter) will change dependant on the key pressed and any modifier keys, so, for example, pressing the left arrow will return code 37, shift-left will return 65573, ctrl-left 131109 and alt-left 262181.
keyData（第二个参数）的值将根据按下的键和任何修饰键而改变，因此，例如，按向左箭头将返回代码 37，shift-left 将返回 65573，ctrl-left 131109 和 alt-left 262181。
You can extract the modifiers and the key pressed by ANDing with appropriate enum values:
您可以使用适当的枚举值提取修饰符和通过 AND 按下的键：
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
bool shiftPressed = (keyData & Keys.Shift) != 0;
Keys unmodifiedKey = (keyData & Keys.KeyCode);
// rest of code goes here
}
回答by cdiggins
I upvoted Tokabi's answer, but for comparing keys there is some additional advice on StackOverflow.com here. Here are some functions which I used to help simplify everything.
我赞成Tokabi 的回答，但为了比较密钥，StackOverflow.com上还有一些额外的建议。以下是我用来帮助简化一切的一些功能。
public Keys UnmodifiedKey(Keys key)
{
return key & Keys.KeyCode;
}
public bool KeyPressed(Keys key, Keys test)
{
return UnmodifiedKey(key) == test;
}
public bool ModifierKeyPressed(Keys key, Keys test)
{
return (key & test) == test;
}
public bool ControlPressed(Keys key)
{
return ModifierKeyPressed(key, Keys.Control);
}
public bool AltPressed(Keys key)
{
return ModifierKeyPressed(key, Keys.Alt);
}
public bool ShiftPressed(Keys key)
{
return ModifierKeyPressed(key, Keys.Shift);
}
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
if (KeyPressed(keyData, Keys.Left) && AltPressed(keyData))
{
int n = code.Text.IndexOfPrev('<', code.SelectionStart);
if (n < 0) return false;
if (ShiftPressed(keyData))
{
code.ExpandSelectionLeftTo(n);
}
else
{
code.SelectionStart = n;
code.SelectionLength = 0;
}
return true;
}
else if (KeyPressed(keyData, Keys.Right) && AltPressed(keyData))
{
if (ShiftPressed(keyData))
{
int n = code.Text.IndexOf('>', code.SelectionEnd() + 1);
if (n < 0) return false;
code.ExpandSelectionRightTo(n + 1);
}
else
{
int n = code.Text.IndexOf('<', code.SelectionStart + 1);
if (n < 0) return false;
code.SelectionStart = n;
code.SelectionLength = 0;
}
return true;
}
return base.ProcessCmdKey(ref msg, keyData);
}
