WPF C＃画布绘图线连接按钮

Question

我测试了如何绘制在点击按钮按钮连接到另一个按钮一条线，我得到的坐标和迷惑settop setleft ，他们是如何在实际深入浅出工作。 我知道我们必须设置直线的X2 Y2 （起点与终点的差值），但是我真的对减法以及如何做到这一点感到困惑。

到目前为止，这是我尝试过的：

 int k = 20;
 for (int i = 0; i < 4; i++)
 {
      Button btn = new Button();
      btn.Content = i.ToString();
      btn.Height = 20;
      btn.Width = 20;
      Canvas.SetTop(btn,k); // 20
      Canvas.SetLeft(btn, 20); // 10 
      Canvas1.Children.Add(btn);
      btn.PreviewMouseDown += (source, e) =>
      {
          // No idea how to set X2 , Y2 for the line's end point.
          Line line = new Line();
          //line.X2 = ;
          //line.Y2 = ;
          line.Stroke = Brushes.Red;
          line.StrokeThickness = 4;
          Canvas.SetLeft(line,40); // Suppose this is where the line should start 
          Canvas.SetTop(line ,40); // for button " 0 " .
          Canvas1.Children.Add(line);
      };
      k += 20;
 }
 for (int i = 0; i < 4; i++)
 {
      Button btn2 = new Button();
      btn2.Content = i.ToString();
      btn2.Height = 20;
      btn2.Width = 20;
      Canvas.SetTop(btn2, k); // 20
      Canvas.SetRight(btn2, 20); // 10
      Canvas1.Children.Add(btn2);
      btn2.PreviewMouseDown += (source, e) =>
      {
          //Draw Line to connect here.
      };
      k += 20;
  }

我正在尝试从btn到btn2划清界限。

而且，我如何将按钮调整为同一水平，因为现在右按钮（btn2）比左按钮（btn）略低，我想画一条线将右按钮连接到左按钮在单击按钮0时，因此0将在0处画一条线。

Answer 1

尽管可以通过移动Canvas来做到这一点，但最好还是使用Buttons本身在Canvas上的位置。

本质上，您需要具有两组坐标，即LineStart和LineEnd ，在这种情况下，这是从您单击的两个不同Buttons获得的。

您可以使用Point location = ((Button)source).TransformToAncestor(Canvas1).Transform(new Point(0, 0))获得相对于父级Canvas而言被单击的按钮的位置。

然后，您需要做类似的事情来找到您单击的原始对象的位置（您似乎没有在存储它）。 然后，您可以通过设置X1, X2, Y1, Y2值在两个计算的Points之间简单地画一条线。

改编您的示例，您可以执行以下操作（仅用于演示）：

public partial class MainWindow : Window
{
    public Button LastClicked { get; set; }

    public MainWindow()
    {
        InitializeComponent();

        InitButtons();
    }


    public void InitButtons()
    {
        int k = 20;

        for (int i = 0; i < 4; i++)
        {
            Button btn = new Button();
            btn.Content = i.ToString();
            btn.Height = 20;
            btn.Width = 20;
            Canvas.SetTop(btn, k); // 20
            Canvas.SetLeft(btn, 20); // 10 
            Canvas1.Children.Add(btn);
            btn.PreviewMouseDown += (source, e) =>
            {
                if (LastClicked != null)
                {
                    // Get button locations.
                    Point LastClickedLocation = LastClicked.TransformToAncestor(Canvas1).Transform(new Point(0, 0));
                    Point ThisClickedLocation = ((Button)source).TransformToAncestor(Canvas1).Transform(new Point(0, 0));

                    // Stop same side lines.
                    if (LastClickedLocation.X != ThisClickedLocation.X)
                    {
                        Line line = new Line();

                        line.X1 = LastClickedLocation.X;
                        line.Y1 = LastClickedLocation.Y + btn.Height / 2; // Button Middle.
                        line.X2 = ThisClickedLocation.X + btn.Width; // Adjust Left side.
                        line.Y2 = ThisClickedLocation.Y + btn.Height / 2; // Button Middle.

                        line.Stroke = Brushes.Red;
                        line.StrokeThickness = 4;

                        Canvas1.Children.Add(line);
                    }
                }

                LastClicked = (Button)source;
            };
            k += 20;
        }

        k = 20; // Reset k, this is why your buttons weren't aligned.

        for (int i = 0; i < 4; i++)
        {
            Button btn2 = new Button();
            btn2.Content = i.ToString();
            btn2.Height = 20;
            btn2.Width = 20;
            Canvas.SetTop(btn2, k); // 20
            Canvas.SetRight(btn2, 20); // 10
            Canvas1.Children.Add(btn2);

            btn2.PreviewMouseDown += (source, e) =>
            {
                if (LastClicked != null)
                {
                    // Get button locations.
                    Point LastClickedLocation = LastClicked.TransformToAncestor(Canvas1).Transform(new Point(0, 0));
                    Point ThisClickedLocation = ((Button)source).TransformToAncestor(Canvas1).Transform(new Point(0, 0));

                    // Stop same side lines.
                    if (LastClickedLocation.X != ThisClickedLocation.X)
                    {
                        Line line = new Line();

                        line.X1 = LastClickedLocation.X + btn2.Width; // Adjust Left side.
                        line.Y1 = LastClickedLocation.Y + btn2.Height / 2; // Button Middle.
                        line.X2 = ThisClickedLocation.X;
                        line.Y2 = ThisClickedLocation.Y + btn2.Height / 2; // Button Middle.

                        line.Stroke = Brushes.Red;
                        line.StrokeThickness = 4;

                        Canvas1.Children.Add(line);
                    }
                }

                LastClicked = (Button)source;
            };
            k += 20;
        }
    }
}

我不建议使用此确切的代码，因为它在处理Button单击和确定何时绘制线条方面并不是特别出色，但是它应该演示绘制并获取您要使用的坐标。