WPF Mousedown =>没有MouseLeave事件

Question

我正在使用Microsoft Blend构建Windows Presentation Foundation控件.

当我通过按下鼠标左键离开我的控件时,不会引发MouseLeave-Event.为什么不？

Answer 1

这是预期的行为:当您mousedown在控件上执行并离开控件时,控件STILL会在鼠标上保留其"捕获",这意味着控件不会触发控件MouseLeave-Event.一旦将鼠标按钮释放到控件之外,鼠标离开事件将被触发.

为避免这种情况,您可以简单地告诉控件不要捕获鼠标:

private void ControlMouseDown(System.Object sender, System.Windows.Forms.MouseEventArgs e)
{
    Control control = (Control) sender;
    control.Capture = false; //release capture.
}

现在,即使在按下按钮时移出,MouseLeave事件也会被触发.

如果您需要Capture INSIDE the Control,您需要付出更多努力:

• 按下鼠标键时,手动开始跟踪鼠标位置

• 比较的位置Top,Left并Size在讨论的控件的属性.

• 决定是否需要停止控制捕获鼠标.

  public partial class Form1 : Form
  {
  private Point point;
  private Boolean myCapture = false;
  
  public Form1()
  {
      InitializeComponent();
  }
  
  private void button1_MouseDown(object sender, MouseEventArgs e)
  {
      myCapture = true;
  }
  
  private void button1_MouseMove(object sender, MouseEventArgs e)
  {
      if (myCapture)
      {
          point = Cursor.Position;
  
          if (!(point.X > button1.Left && point.X < button1.Left + button1.Size.Width && point.Y > button1.Top && point.Y < button1.Top + button1.Size.Height))
          {
              button1.Capture = false; //this will release the capture and trigger the MouseLeave event immediately.
              myCapture = false;
          }
      }
  }
  
  private void button1_MouseLeave(object sender, EventArgs e)
  {
      MessageBox.Show("Mouse leaving");
  }
  

  }

当然你需要myCapture=false;在MouseUp上停止自己的tracking().忘了一个:)