这里先封装一个方法，使用的时候先创建一个Draw，拿到DrawingContext 之后就可以通过DrawingContext 去绘制想要的图形，绘制完成后通过GetDraw拿到所有绘制的结果
添加一个PrintImage()用于测试当前绘图的样子用于测试

   public class DrawVector{public DrawingVisual? visual { get; set; }public DrawingContext CreateDraw(){if (visual == null)visual = new DrawingVisual();var dc = visual.RenderOpen();return dc;}public DrawingGroup? GetDraw(DrawingContext? dc){if (visual == null)return null;if (dc == null)return null;Dispose(dc);var draw = visual.Drawing.Frozen();//PrintImage();return draw;}/// <summary>/// 测试打印绘图结果/// </summary>private void PrintImage(){var bmp = new RenderTargetBitmap(2000, 2000, 96, 96, PixelFormats.Pbgra32);bmp.Render(visual);var encoder = new PngBitmapEncoder();encoder.Frames.Add(BitmapFrame.Create(bmp));using (var stream = new FileStream($"D:\\{Guid.NewGuid()}.png", FileMode.Create)){encoder.Save(stream);}}public void RotationAngle(DrawingContext dc, Rect rect, double angleInDegrees){var rotateTransform = new RotateTransform(angleInDegrees, rect.X + rect.Width / 2, rect.Y + rect.Height / 2);dc.PushTransform(rotateTransform);}private void Dispose(DrawingContext? dc){if (dc != null)dc.Close();}}

使用实例

   var drawVector = new DrawVector();var dc = drawVector.CreateDraw();dc.DrawRectangle(System.Windows.Media.Brushes.White, new System.Windows.Media.Pen(System.Windows.Media.Brushes.White, 1).Frozen(), new Rect(0, 0, MapBackCanvasWidth, MapBackCanvasHeight));DrawVectorContent(dc);return drawVector.GetDraw(dc);