鼠标左键在需要的时候没有被触发

任务:我有一个简单的任务要执行:在椭圆内围绕椭圆的中心移动一根针。它是成为一个角度计指示/控制。

状态:

当左键在椭圆内时，我想根据鼠标位置移动此指针。

这是好的。

我想要停止移动，如果鼠标左键被释放。

可以。

我问题:

但问题是，如果我退出椭圆区域与鼠标左键按下(即偶然，当移动指针)，那么它是"持有"。如果您曾经回到椭圆与鼠标左键向上，针将移动，如果它被点击。所以我需要的是禁用"拖动"当我的鼠标离开椭圆，无论鼠标左键被点击与否。此时，如果指针处于"锁定"状态，则需要到椭圆外，点击鼠标左键，进入椭圆区域保持按下。如果你现在释放鼠标左键，它将恢复到正常/想要的行为。

下面是我的XAML "code":

<Window x:Class="test_gauge.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid MouseLeftButtonUp="Grid_MouseLeftButtonUp">
        <Ellipse Name="ellipse1" Fill="#FFF4F4F5" HorizontalAlignment="Left" Height="100" Stroke="Black" VerticalAlignment="Top" Width="100" Canvas.Left="0" Canvas.Top="0" Margin="280,180,0,0" MouseMove="onEllipseMouseMove" MouseLeftButtonDown="onEllipseMouseLeftPressed" MouseLeftButtonUp="onEllipseMouseLeftReleased" MouseLeave="onEllipseMouseLeave"/>
        <Canvas Margin="257,145,10,10" MouseLeftButtonUp="Canvas_MouseLeftButtonUp_1">
            <Thumb Name="myThumb" Canvas.Left="73" Canvas.Top="85" RenderTransformOrigin="0,0">
                <Thumb.RenderTransform>
                    <RotateTransform/>
                </Thumb.RenderTransform>
                <Thumb.Template>
                    <ControlTemplate>
                        <Line Name="needle_line" X1="0" Y1="0" X2="50" Y2="0" StrokeThickness="2" Stroke="Black" MouseLeave="needle_line_MouseLeave"/>
                    </ControlTemplate>
                </Thumb.Template>
            </Thumb>
            <TextBox Name="txtbxAngle" Height="23" Canvas.Left="168" TextWrapping="Wrap" Text="TextBox" Canvas.Top="25" Width="72"/>
        </Canvas>
    </Grid>
</Window>

然后c# "code":

public partial class MainWindow : Window
{
    /* Angle control stuff */
    public bool bNeedlePressed = false;
    public double refreshedAngle = 0;
    public MainWindow()
    {
        InitializeComponent();
    }
    private void onEllipseMouseMove(object sender, MouseEventArgs e)
    {
        if (bNeedlePressed)
        {
            // This will get the mouse cursor relative to the upper left corner of your ellipse.
            // Note that nothing will happen until you are actually inside of your ellipse.
            Point curPoint = e.GetPosition(ellipse1);
            // Assuming that your ellipse is actually a circle.
            Point center = new Point(ellipse1.Width / 2, ellipse1.Height / 2);
            // A bit of math to relate your mouse to the center...
            Point relPoint = new Point(curPoint.X - center.X, curPoint.Y - center.Y);
            /* Process new angle */
            refreshedAngle = Math.Atan2(relPoint.Y, relPoint.X) * 180 / Math.PI;
            txtbxAngle.Text = ((int)(refreshedAngle)).ToString();
            /* Apply new angle */
            var transform = myThumb.RenderTransform as RotateTransform;
            transform.Angle = refreshedAngle;
        }
    }
    private void onEllipseMouseLeftPressed(object sender, MouseButtonEventArgs e)
    {
        bNeedlePressed = true;
    }
    private void Canvas_MouseLeftButtonUp_1(object sender, MouseButtonEventArgs e)
    {
        bNeedlePressed = false;
    }
    private void onEllipseMouseLeftReleased(object sender, MouseButtonEventArgs e)
    {
        bNeedlePressed = false;
    }
    private void onEllipseMouseLeave(object sender, MouseEventArgs e)
    {
        //bNeedlePressed = false;
    }
    private void needle_line_MouseLeave(object sender, MouseEventArgs e)
    {
        //bNeedlePressed = false;
    }
    private void Grid_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
    {
        bNeedlePressed = false;
    }
}

如您所见，它可以使用不同的事件，但没有一个能达到目的。好吧，我相信至少有一个，但我不知道是哪一个。

如果你有什么想法，请随时回答:)

    private void Grid_MouseLeave(object sender, MouseEventArgs e)
    {
        bNeedlePressed = false;
    }

<Grid MouseLeftButtonUp="Grid_MouseLeftButtonUp" MouseLeave="Grid_MouseLeave" MouseEnter="Grid_MouseEnter">

    private void Grid_MouseEnter(object sender, MouseEventArgs e)
    {
        bNeedlePressed = e.LeftButton == MouseButtonState.Pressed;
    }