/// <summary> /// 按下鼠标左键移动 /// </summary> private void Canvas_PreviewMouseMove(object sender, MouseEventArgs e) { if (e.LeftButton == MouseButtonState.Pressed) { // 返回指针相对于Canvas的位置 Point point = e.GetPosition(myCanvas); if (pointList.Count == 0) { // 加入起始点 pointList.Add(new Point(this.startPoint.X, this.startPoint.Y)); } else { // 加入移动过程中的point pointList.Add(point); } // 去重复点 var disList = pointList.Distinct().ToList(); var count = disList.Count(); // 总点数 if (point != this.startPoint && this.startPoint != null) { var l = new Line(); string color = (cboColor.SelectedItem as ComboBoxItem).Content as string; if (color == "默认") { l.Stroke = Brushes.Black; } if (color == "红色") { l.Stroke = Brushes.Red; } if (color == "绿色") { l.Stroke = Brushes.Green; } l.StrokeThickness = 1; if (count < 2) return; l.X1 = disList[count - 2].X; // count-2 保证 line的起始点为点集合中的倒数第二个点。 l.Y1 = disList[count - 2].Y; // 终点X,Y 为当前point的X,Y l.X2 = point.X; l.Y2 = point.Y; myCanvas.Children.Add(l); } } }
       移动过程中创建Line对象并加入Canvas中。    代码中的颜色判断最好修改成枚举类型。