public void SetWindowRegion() { System.Drawing.Drawing2D.GraphicsPath FormPath; FormPath = new System.Drawing.Drawing2D.GraphicsPath(); Rectangle rect = new Rectangle(0, 0, this.Width, this.Height); FormPath = WinGetRoundedRectPath(rect, 15); this.Region = new Region(FormPath); } private GraphicsPath WinGetRoundedRectPath(Rectangle rect, int radius) { int diameter = radius; Rectangle arcRect = new Rectangle(rect.Location, new Size(diameter, diameter)); GraphicsPath path = new GraphicsPath(); // 左上角 path.AddArc(arcRect, 180, 90); // 右上角 arcRect.X = rect.Right - diameter; path.AddArc(arcRect, 270, 90); // 右下角 arcRect.Y = rect.Bottom - diameter; path.AddArc(arcRect, 0, 90); // 左下角 arcRect.X = rect.Left; path.AddArc(arcRect, 90, 90); path.CloseFigure(); return path; }