WPF在CaptureMouse（）後不發送MouseMove事件;

Question

我想要一個帶圓角矩形的WPF畫布，我可以用鼠標拖動。但是，一旦我嘗試在畫布上捕獲鼠標，我就不會再收到移動事件了。

這是一個「mycanvas」用戶控件，矩形是「foo」用戶控件。在XAML這些（減去前序）是：

mycanvas.xaml：

<Canvas MouseDown="CanvasMouseDown" MouseMove="CanvasMouseMove" MouseUp="CanvasMouseUp" Background="White"> 

    <my:Foo HorizontalAlignment="Left" Canvas.Left="97" Canvas.Top="30" x:Name="m_foo" VerticalAlignment="Top" Height="87" Width="128" /> 
</Canvas> 

foo.xaml：

<Border BorderThickness="2" BorderBrush="Black" CornerRadius="15" Background="Plum"> 
    <Grid> 
     <Label Content="Foo" Height="28" HorizontalAlignment="Left" Margin="6,6,0,0" Name="label1" VerticalAlignment="Top" /> 
    </Grid> 
</Border> 

然後是處理程序是： mycanvas.xaml.cs：

private void CanvasMouseDown(object sender, MouseButtonEventArgs e) 
{ 
    if (e.Source is Foo) 
    { 
     m_moving = e.Source as Foo; 
     CaptureMouse(); 
     e.Handled = true; 
    } 
} 

private void CanvasMouseMove(object sender, MouseEventArgs e) 
{ 
    if (m_moving != null) 
    { 
     Canvas.SetLeft(m_moving, e.GetPosition(this).X); 
     Canvas.SetTop(m_moving, e.GetPosition(this).Y); 
    } 
} 

private void CanvasMouseUp(object sender, MouseButtonEventArgs e) 
{ 
    ReleaseMouseCapture(); 
    m_moving = null; 
} 

MouseDown會發生火災，所以CaptureMouse會被調用（並且因爲我無法再修復選擇應用程序或單擊其中的任何內容！）但MouseMove永遠不會被調用 - 那麼MouseMove事件現在發送到哪裏？

如果我alt選項卡到另一個應用程序，然後現在回去suddendly調用MouseMove和Foo隨鼠標移動。

Answer 1

儘量之一：

Mouse.Capture(this, CaptureMode.SubTree); 

或

m_moving.CaptureMouse(); 
... 
if (m_moving != null) 
{ 
    m_moving.ReleaseMouseCapture(); 
    m_moving = null; 
} 

鼠標事件正由美孚提出的，而不是由畫布，所以當你捕獲鼠標與畫布可以防止它們被提出。

Answer 2

您可以直接使用窗口MouseMove事件：

public partial class MainWindow : Window 
{ 
    public MainWindow() 
    { 
     InitializeComponent(); 

     this.MouseMove += MouseEventHandler; 

    } 

    private void MouseEventHandler(Object sender, MouseEventArgs e) 
    { 
     System.Windows.Point position = e.GetPosition(this); 

     Canvas.SetLeft(ElipseElement, position.X-5); 
     Canvas.SetTop(ElipseElement, position.Y-5);  


    } 
}