WPF在CaptureMouse()之后不发送MouseMove事件;

Question

我正在尝试使用带有圆角矩形的WPF画布,我可以使用鼠标拖动它.然而,一旦我尝试在画布上捕获鼠标,我就不再获得移动事件了.

这是一个"mycanvas"用户控件,矩形是"foo"用户控件.这些(减去前言)的XAML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>

然后处理程序是: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触发,因此CaptureMouse被调用(并且因为我无法再关闭应用程序或单击其中任何其他内容而工作!)但MouseMove再也不会被调用 - 所以MouseMove事件现在在哪里被发送？

如果我alt-tab到另一个应用程序,然后现在回到现在突然调用MouseMove并且Foo随鼠标移动.

Answer 1

尝试:

Mouse.Capture(this, CaptureMode.SubTree);

要么

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

鼠标事件是由Foo引发的,而不是由Canvas引发的,因此当您使用Canvas捕获鼠标时,可以防止它们被引发.