用C#可以画圆，椭圆，但是怎么画一个矩形？
郁闷，这个都不会。

怎么没有人回啊

画矩形也可以啊。
Graphics graphics = this.CreateGraphics();
            graphics.Clear(Color.White);
            SolidBrush greenBrush = new SolidBrush(Color.Green);
            PointF point1 = new PointF(100.0f, 100.0f);
            PointF point2 = new PointF(200.0f, 50.0f);
            PointF point3 = new PointF(250.0f, 200.0f);
            PointF point4 = new PointF(50.0f, 150.0f);
            PointF point5 = new PointF(100.0f, 100.0f);
            PointF[] points = new PointF[] { point1, point2, point3, point4 };
            graphics.FillClosedCurve(greenBrush, points, FillMode.Alternate, 1.0f);
            PointF[] poly = new PointF[] { point1, point2, point3, point4, point5 };
            graphics.TranslateTransform(300, 0);
            graphics.FillPolygon(greenBrush, poly, FillMode.Alternate);
这里二个多边型的代码，你可以自己更改坐标后就可以画成矩形 了。