private void MyControl_MouseMove(object sender, MouseEventArgs e) { if(sender is UIElement uIElement) { if (isDragging) { Point newPoint = e.GetPosition(canvas); double deltaX = newPoint.X - startPoint.X; double deltaY = newPoint.Y - startPoint.Y; Canvas.SetLeft(uIElement, Canvas.GetLeft(uIElement) + deltaX); Canvas.SetTop(uIElement, Canvas.GetTop(uIElement) + deltaY); startPoint = newPoint; } } } private void MyControl_MouseDown(object sender, MouseButtonEventArgs e) { if (sender is UIElement uIElement) { isDragging = true; startPoint = e.GetPosition(canvas); uIElement.CaptureMouse(); } } private void MyControl_MouseUp(object sender, MouseButtonEventArgs e) { if (sender is UIElement uIElement) { isDragging = false; uIElement.ReleaseMouseCapture(); } }令移动的控件不超过Canvas的边界

可以在 `MyControl_MouseMove` 方法中添加一些代码来检查移动的控件是否超过了 `Canvas` 的边界。具体实现方法如下：

private void MyControl_MouseMove(object sender, MouseEventArgs e)
{
    if (sender is UIElement uIElement)
    {
        if (isDragging)
        {
            Point newPoint = e.GetPosition(canvas);
            double deltaX = newPoint.X - startPoint.X;
            double deltaY = newPoint.Y - startPoint.Y;

            // 计算控件新的位置
            double newX = Canvas.GetLeft(uIElement) + deltaX;
            double newY = Canvas.GetTop(uIElement) + deltaY;

            // 检查控件是否超过 Canvas 的边界
            if (newX < 0)
            {
                newX = 0;
            }
            else if (newX + uIElement.ActualWidth > canvas.ActualWidth)
            {
                newX = canvas.ActualWidth - uIElement.ActualWidth;
            }

            if (newY < 0)
            {
                newY = 0;
            }
            else if (newY + uIElement.ActualHeight > canvas.ActualHeight)
            {
                newY = canvas.ActualHeight - uIElement.ActualHeight;
            }

            Canvas.SetLeft(uIElement, newX);
            Canvas.SetTop(uIElement, newY);

            startPoint = newPoint;
        }
    }
}

在上述代码中，我们首先计算出控件的新位置 `newX` 和 `newY`，然后通过一些判断来确保控件不超过 `Canvas` 的边界。如果控件超过了边界，则将其位置设置为边界的位置。最后，我们调用 `Canvas.SetLeft` 和 `Canvas.SetTop` 方法来更新控件的位置。