wpf中在Canvas中定义的线条不显示解决方法

wpf中在Canvas中定义的线条不显示
for (j = 0; j < count - 1; j++)
                {
                    Point startPoint=new Point(data[j, 0],data[j, 1]);
                    Point endPoint=new Point(data[j + 1, 0],data[j + 1, 1]);
                    LineGeometry LG = new LineGeometry();
                    LG.StartPoint = startPoint;
                    
                    LG.EndPoint =endPoint;
                   
                    myGeometryGroup.Children.Add(LG);
                   }
      Path mypath = new Path();
            mypath.Stroke = Brushes.Red;
            DoubleCollection dashs = new DoubleCollection();
            //dashs.Add(2);//画虚线
            //dashs.Add(2);//画虚线
            mypath.StrokeDashArray = dashs;
            mypath.StrokeThickness = 1.5;
            mypath.Data = myGeometryGroup;
            Canvas1.Children.Add(mypath);
其中data是一个double型的二维数组，请问为什么只显示了窗体，不显示线条呢？希望各位大神帮解决一下   谢了！！！
[解决办法]