导致调用方法的组合键 (CTRL + F9) 应仅在按下 F9 时调用

Question

我正在开发 WPF 应用程序，当按下组合键时我会显示 modal/form，所以在我的例子中是 CTRL + F9， 所以这是我的代码：

//Listening on Window_PreviewKeyDown any key pressing
private void Window_PreviewKeyDown(object sender, KeyEventArgs e)
{ 

 if (e.Key == Key.Escape)
 {
    LockAllInputs();
 }

 if (e.Key == Key.Tab)
 {
    e.Handled = true;
 }

 if (e.Key == Key.F11)
 {
     this.Close();
 }
   // Opening modal when Key combination of CTRL AND F9 is pressed
   if (Keyboard.Modifiers == ModifierKeys.Control && e.Key == Key.F9)
   {
     MyModal modal = new MyModal();
    // Do something
   }

   //Hitting a method when only F9 is pressed
    if (e.Key == Key.F9)
    {
      //This is invoked everytime after CTRL+F9
      CallAnotherMethod();
    }
}

但是我的代码中的问题是，当我点击 CTRL+F9 时它工作正常，但是在按下 F9 时调用的那个方法也被调用.. 这是我想避免的事情，CTRL+F9 正在做一件事，F9 正在做另一件事，所以我不希望在按下 CTRL+F9 时调用 F9...

谢谢大家

Answer 1

您只是在检查 F9 键是否是触发事件的键，而不是在检查是否还按下了任何其他键。您有 2 个解决方案：

1. 将第二个 if 更改为 if else;
2. 检查是否没有按下其他修饰符。

Answer 2

if (Keyboard.Modifiers == ModifierKeys.Control && e.Key == Key.F9)
{
  MyModal modal = new MyModal();
  modal.ShowDialog();
  e.Handled = true;//Here I've tried to prevent hitting another method which is being called when F9 is pressed
 }

//Hitting a method when only F9 is pressed
if (e.Key == Key.F9)
{
  //This is invoked everytime after CTRL+F9
  CallAnotherMethod();
}

您的代码将在 第一个 if 之后继续执行 ，因此也将进入第二个 if。

最简单的解决方案是将第二个 if 更改为 else if:

else if (e.Key == Key.F9)
{
  //This is invoked everytime after CTRL+F9
  CallAnotherMethod();
}

另一种选择是停止执行函数 inside 第一个 if:

if (Keyboard.Modifiers == ModifierKeys.Control && e.Key == Key.F9)
{
  MyModal modal = new MyModal();
  modal.ShowDialog();
  e.Handled = true;
  return;
}

Answer 3

应该是这样的：

    //Listening on Window_PreviewKeyDown any key pressing
private void Window_PreviewKeyDown(object sender, KeyEventArgs e)
{ 

 if (e.Key == Key.Escape)
 {
    LockAllInputs();
 }

 if (e.Key == Key.Tab)
 {
    e.Handled = true;
 }

 if (e.Key == Key.F11)
 {
     this.Close();
 }
   // Opening modal when Key combination of CTRL AND F9 is pressed
   if (Keyboard.Modifiers == ModifierKeys.Control && e.Key == Key.F9)
   {
     MyModal modal = new MyModal();
     modal.ShowDialog();
     e.Handled = true;//Here I've tried to prevent hitting another method which is being called when F9 is pressed
   }

   //Hitting a method when only F9 is pressed
    if (Keyboard.Modifiers == ModifierKeys.None && e.Key == Key.F9)
    {
      CallAnotherMethod();
    }
}