PreviewMouseMove无法正常工作

问题描述

您好专家，

我正在使用WPF和C#.在此，我正在使用图像上的面板数.并尝试使用e.LeftButton == MouseButtonState.Pressed在图像上移动面板.它可以正确移动，但是当一个面板在另一面板上覆盖时，PreviewMouseMove会保留较旧的面板，然后拾取新的面板.

使用此代码:

Hello Experts,

I am working with WPF and C#. In this I am using number of panels on image. and trying to move panels over an image using e.LeftButton == MouseButtonState.Pressed.Its moving properly but when one panel override on another panel PreviewMouseMove leaves older one and pick up new one.

Using this code:

void panel_PreviewMouseMove(object sender, MouseEventArgs e)
{
    Point x = e.GetPosition(ImageHolder);
    StackPanel panel = (StackPanel)sender;
    if (e.LeftButton == MouseButtonState.Pressed && !dragging)
    {
        dragging = true;
               
        //restrict dropped camera image to be in map image area 
        if ((Canvas.GetLeft(panel) + (x.X - p.X)) <= (Img.Width - panel.Width) && (Canvas.GetLeft(panel) + (x.X - p.X)) >= 0)
        {
            Canvas.SetLeft(panel, Canvas.GetLeft(panel) + (x.X - p.X));
        }

        if ((Canvas.GetTop(panel) + (x.Y - p.Y)) <= (Img.Height - panel.Height) && (Canvas.GetTop(panel) + (x.Y - p.Y)) >= 0)
        {
            Canvas.SetTop(panel, Canvas.GetTop(panel) + (x.Y - p.Y));
        }
    }
    else if (e.LeftButton == MouseButtonState.Released)
    {
        dragging = false;             
    }

    p = x; 
}

向我建议一些修改或其他选择.

谢谢

Suggest me some modifications or else any alternative.

Thanks

推荐答案

StackPanel panel;

void panel_PreviewMouseMove(object sender, MouseEventArgs e)
{
    Point x = e.GetPosition(ImageHolder);

    if (e.LeftButton == MouseButtonState.Pressed)
    {
        if (panel == null)
        {
            panel = (StackPanel)sender;
        }

        //restrict dropped camera image to be in map image area
        if ((Canvas.GetLeft(panel) + (x.X - p.X)) <= (Img.Width - panel.Width) && (Canvas.GetLeft(panel) + (x.X - p.X)) >= 0)
        {
            Canvas.SetLeft(panel, Canvas.GetLeft(panel) + (x.X - p.X));
        }

        if ((Canvas.GetTop(panel) + (x.Y - p.Y)) <= (Img.Height - panel.Height) && (Canvas.GetTop(panel) + (x.Y - p.Y)) >= 0)
        {
            Canvas.SetTop(panel, Canvas.GetTop(panel) + (x.Y - p.Y));
        }
    }
    else if (e.LeftButton == MouseButtonState.Released)
    {
        panel = null;
    }

    p = x;
}

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