selection-rectangle（用鼠标在 canvas 上绘制）无法识别 selection-rectangle 内的矩形 (C# WPF)

Question

我现在真的很绝望。我只是不能再进一步了，原则上它不应该那么困难。我在过去两周尝试解决它。以下task/problem：我的 C# WPF 项目中有一个名为“MarkPointsMap”的 canvas，上面有不同类型的标记点（3 种不同颜色的矩形）。一个 MarkPointsMap 可以包含大约 3000-4000 个不同的 MarkPoints（Children of that canvas）遍布整个 MarkPointsMap。该 MarkPoints 的位置是从 .tab-file 加载的，它被转换成一个名为“MarkPoints”的列表，并在加载相应的 .tab-file.

这是 MarkPointsMap 的屏幕截图：

有例如大多数是小矩形（绿色的），一些中间的矩形（黄色的）和两个大矩形（红色的）。应使用 selection-rectangle 选择多个标记点。在我的项目中，我已经可以绘制选择矩形，但是“if this.selectRect.Contains(MarkPointsMap.Children)”（见下文）部分不起作用。

selection-rectangle 看起来如下：

程序中加载.tab文件后调用的drawMarkPoints方法在canvas“MarkPointsMap”上绘制标记点：

public void drawMarkPoints()
    {
        MarkPointsMap.Children.Clear();

        foreach (MarkPoint markpoint in this.Marks.markpoints)
        {
            if (markpoint.type.relevant)
            {
                Rectangle markpointArea = new Rectangle();
                markpointArea.Tag = markpoint;
                //!!
                SolidColorBrush mySolidColorBrush = new SolidColorBrush();
                mySolidColorBrush.Color = markpoint.fillColor;
                markpointArea.Fill = mySolidColorBrush;
                markpointArea.StrokeThickness = 0.2;
                markpointArea.Stroke = Brushes.Black;

                markpointArea.Width = markpoint.symbol.Width;
                markpointArea.Height = markpoint.symbol.Height;
                //set the markpoints in canvas 
                Canvas.SetLeft(markpointArea, getCanvasCoordinates(markpoint.center).X - 0.5 * markpoint.symbol.Width); 
                Canvas.SetTop(markpointArea, getCanvasCoordinates(markpoint.center).Y - 0.5 * markpoint.symbol.Height);

                MarkPointsMap.Children.Add(markpointArea);
          
            }
        }
    }

selection-rectangle是在canvas“MarkPointsMap”中绘制的，三个Mouse-Events（MarkPointsMap_MouseDown、MarkPointsMap_MouseMove、MarkPointsMap_MouseUp） :

public Rect itemRect;
public Rect selectRect;
private point anchorPoint; 
private Rectangle manualDragRect = new Rectangle(); 

private void MarkPointsMap_MouseDown(object sender, MouseButtonEventArgs e)
    {
        if (e.ChangedButton == MouseButton.Left)
        {
            isLeftMouseButtonDownOnWindow = true;
            anchorPoint = e.MouseDevice.GetPosition(MarkPointsMap);
            MarkPointsMap.CaptureMouse();
            e.Handled = true;
            manualDragRect = new Rectangle
            {
                Stroke = Brushes.Red,
                StrokeThickness = 2
            };
            MarkPointsMap.Children.Add(manualDragRect); 
        }       
    }

private void MarkPointsMap_MouseMove(object sender, MouseEventArgs e)
    {
        if (!MarkPointsMap.IsMouseCaptured)
            return;

        Point location = e.MouseDevice.GetPosition(MarkPointsMap);
        double minX = Math.Min(location.X, anchorPoint.X);
        double minY = Math.Min(location.Y, anchorPoint.Y);
        double maxX = Math.Max(location.X, anchorPoint.X);
        double maxY = Math.Max(location.Y, anchorPoint.Y);

        Canvas.SetTop(manualDragRect, minY);
        Canvas.SetLeft(manualDragRect, minX);

        double height = maxY - minY;
        double width = maxX - minX;

        manualDragRect.Height = Math.Abs(height);
        manualDragRect.Width = Math.Abs(width);
        Point xy_2 = new Point((Canvas.GetLeft(manualDragRect) + 0.5 * width), (Canvas.GetTop(manualDragRect) + 0.5 * height));
        this.selectRect = new Rect(xy_2.X, xy_2.Y, width, height);
    }


private void MarkPointsMap _MouseUp(object sender, MouseButtonEventArgs e)
    {
        MarkPointsMap.ReleaseMouseCapture();

        foreach (MarkPoint markpoint in this.Marks.markpoints) 
        {
            Rect itemRect = new Rect(markpoint.center.X, markpoint.center.Y, markpoint.symbol.Width, markpoint.symbol.Height);
            if (selectRect.Contains(itemRect))
            {
                MessageBox.Show("Test!"); // it does not reach this code, if I circle several markpoints with the red selection-rectangle called “selectRect”
                
            }

        }
    }

为什么这行不通？我想这与从矩形（System.Windows.Shapes 使用描述符）到结构 Rect 的转换有关：IFormattable。未达到的“if (selectRect.Contains(itemRect)”应该在透视中将selection-rectangle内的所有标记点着色为红色，然后计算点(x-Coordinate, y-Coordinate) 的 selection-rectangle 的 middle-point 并将这个中间点添加回原来的 .tab-file.
任何想法或提示，我该如何继续？提前致谢。此致！

Answer 1

看来你的计算有误。您正在抵消 selectRect。您将它相对于呈现的 manualDragRect 居中。这样，您测试的区域与您通过渲染选择边界定义的区域完全不同。

此外，您在 Canvas 上捕获鼠标，但在某些不同的控件上释放捕获。它也应该在 MarkPointsMap 上发布。还要小心将鼠标事件标记为已处理。如果输入处理不是自定义控件的一部分，您通常应该避免使用它。

您应该考虑使用 ItemsControl 和 Canvas 作为面板。然后您可以将绘图移动到标记并为 MarkPoint 数据定义 DataTemplate。

我建议使用从 manualDragRect 形状返回的原始 Rect。这意味着您应该删除 selectRect 字段和相关计算：

private void MarkPointsMap_MouseUp(object sender, MouseButtonEventArgs e)
{
  MarkPointsMap.ReleaseMouseCapture();

  foreach (MarkPoint markpoint in this.Marks.markpoints)
  {
    Rect itemRect = new Rect(markpoint.center.X, markpoint.center.Y, markpoint.symbol.Width, markpoint.symbol.Height);

    Rect selectionBounds = manualDragRect.RenderedGeometry.Bounds;
    selectionBounds.Offset(Canvas.GetLeft(manualDragRect), Canvas.GetTop(manualDragRect));
    if (selectionBounds.Contains(itemRect))
    {
      MessageBox.Show("Test!");
    }

    // TODO::Calculate center of selectionBounds
    Point selectionBoundsCenter = ...;
  }
}

selection-rectangle（用鼠标在 canvas 上绘制）无法识别 selection-rectangle 内的矩形 (C# WPF)

A selection-rectangle (drawn by mouse on canvas) does not recognize rectangles, which are inside that selection-rectangle (C# WPF)

c#

wpf

canvas

selection

rectangles