使用OxyPlot进行橡皮带处理

Question

我在我的应用程序中使用OxyPlot进行制图。我想扩展OxyPlot库以包含橡皮带线系列，类似于折线在CAD应用中可能是橡皮筋的。

我为此写了example。

[Example("LineSeries rubberbanding")]
        public static PlotModel MouseRubberbandingEvent()
        {
          var model = new PlotModel("Rubberbanding",
                                    "Left click to add line and press Esc to end.")
                        {
                                LegendSymbolLength = 40
                        };

          // Add a line series
          var s1 = new LineSeries("LineSeries1")
                     {
                             Color = OxyColors.SkyBlue,
                             MarkerType = MarkerType.Circle,
                             MarkerSize = 6,
                             MarkerStroke = OxyColors.White,
                             MarkerFill = OxyColors.SkyBlue,
                             MarkerStrokeThickness = 1.5
                     };

          model.Series.Add(s1);

          s1.Points.Add(new DataPoint(10,
                                      10));
          IDataPoint tempDataPoint = new DataPoint(0,0);
               s1.Points.Add(tempDataPoint);

               // Remember to refresh/invalidate of the plot
               model.RefreshPlot(false);
          bool isRubberbanding = false;

          // Subscribe to the mouse down event on the line series
          model.MouseDown += (s, e) =>
          {
            // only handle the left mouse button (right button can still be used to pan)
            if (e.ChangedButton == OxyMouseButton.Left)
            {
                s1.Points.Add(s1.InverseTransform(e.Position));
                isRubberbanding = true;
                // Remember to refresh/invalidate of the plot
                model.RefreshPlot(false);
                // Set the event arguments to handled - no other handlers will be called.
                e.Handled = true;

            }
          };

          // Subscribe to the mouse down event on the line series
          s1.MouseDown += (s, e) =>
          {
            // only handle the left mouse button (right button can still be used to pan)
            if (
                (e.ChangedButton == OxyMouseButton.Left)
                &&
                (isRubberbanding)
               )
            {
              s1.Points.Add(s1.InverseTransform(e.Position));
              isRubberbanding = true;
              // Remember to refresh/invalidate of the plot
              model.RefreshPlot(false);
              // Set the event arguments to handled - no other handlers will be called.
              e.Handled = true;

            }
          };

          model.MouseMove += (s, e) =>
          {
            if (isRubberbanding)
            {
              var point = s1.InverseTransform(new ScreenPoint(e.Position.X-8,
                                                              e.Position.Y-8));
              tempDataPoint.X = point.X;
              tempDataPoint.Y = point.Y;
              s1.Points.Remove(tempDataPoint);
              s1.Points.Add(tempDataPoint);
              model.RefreshPlot(false);
            }
          };

          model.MouseUp += (s, e) =>
          {
            if (isRubberbanding)
            {
              s1.LineStyle = LineStyle.Solid;
              model.RefreshPlot(false);
              e.Handled = true;
            }

          };



          return model;
        }

当我将鼠标光标偏移8个像素时，橡皮筋工作正常。但是，当我将光标放在橡皮带线的正下方时，OxyPlot不会触发绘图模型或线系列的鼠标按下事件。

请说明为什么鼠标按下事件没有触发。我已经向OxyPlot提出了相同的question，但没有回复。