WPF悬浮窗MouseLeftButtonUp事件在部分外接鼠标环境下不触发问题

方案1：优化鼠标事件捕获逻辑，避免路由拦截 #

问题核心是外接鼠标场景下MouseLeftButtonDown的事件处理可能抢占了路由，导致后续MouseLeftButtonUp无法传递到悬浮窗。可以通过鼠标捕获和状态跟踪解决：

private bool _isDragging;
private Point _dragStartPoint;

private void FloatingWindow_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    _isDragging = true;
    _dragStartPoint = e.GetPosition(this);
    // 强制捕获鼠标，确保后续Move/Up事件能触发到当前控件
    this.CaptureMouse();
}

private void FloatingWindow_MouseMove(object sender, MouseEventArgs e)
{
    if (!_isDragging) return;
    
    Point currentPos = e.GetPosition(this.Parent as UIElement);
    this.Left = currentPos.X - _dragStartPoint.X;
    this.Top = currentPos.Y - _dragStartPoint.Y;
}

private void FloatingWindow_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
    if (!_isDragging) return;
    
    _isDragging = false;
    this.ReleaseMouseCapture();
    
    // 通过移动距离区分"点击"和"拖动"：距离小于阈值则触发打开窗口
    Point currentPos = e.GetPosition(this);
    if (Math.Abs(currentPos.X - _dragStartPoint.X) < 5 && 
        Math.Abs(currentPos.Y - _dragStartPoint.Y) < 5)
    {
        OpenNewWindow();
    }
}

// 额外订阅窗口级别的MouseUp，防止鼠标移出悬浮窗后无法触发结束逻辑
private void MainWindow_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
    if (_isDragging)
    {
        _isDragging = false;
        floatingWindow.ReleaseMouseCapture();
    }
}

方案2：改用Pointer事件替代Mouse事件（WPF 4.5+） #

Pointer事件是更底层的统一输入事件，兼容鼠标、触摸、笔输入，不会出现Mouse事件的路由异常问题：

private bool _isDragging;
private Point _dragStartPoint;

private void FloatingWindow_PointerPressed(object sender, PointerRoutedEventArgs e)
{
    var pointerPoint = e.GetCurrentPoint(this);
    if (pointerPoint.Properties.IsLeftButtonPressed)
    {
        _dragStartPoint = pointerPoint.Position;
        _isDragging = true;
        this.CapturePointer(e.Pointer);
    }
}

private void FloatingWindow_PointerMoved(object sender, PointerRoutedEventArgs e)
{
    if (!_isDragging || !e.Pointer.IsInContact) return;
    
    var currentPoint = e.GetCurrentPoint(this.Parent as UIElement);
    this.Left = currentPoint.Position.X - _dragStartPoint.X;
    this.Top = currentPoint.Position.Y - _dragStartPoint.Y;
}

private void FloatingWindow_PointerReleased(object sender, PointerRoutedEventArgs e)
{
    if (!_isDragging) return;
    
    _isDragging = false;
    this.ReleasePointerCapture(e.Pointer);
    
    var currentPoint = e.GetCurrentPoint(this);
    if (Math.Abs(currentPoint.Position.X - _dragStartPoint.X) < 5 &&
        Math.Abs(currentPoint.Position.Y - _dragStartPoint.Y) < 5)
    {
        OpenNewWindow();
    }
}

方案3：检查事件拦截标记 #

如果你的MouseLeftButtonDown处理方法中调用了e.Handled = true，会阻止事件向上路由，导致MouseLeftButtonUp无法触发。若必须标记事件已处理，可改用PreviewMouseLeftButtonDown和PreviewMouseLeftButtonUp这类隧道事件，它们的触发优先级更高，不易被拦截。

内容的提问来源于stack exchange，提问作者TonWin