摘要

在C#中，使用GDI+（Graphics Device Interface Plus）可以绘制各种图形，包括多边形。DrawPolygon方法是用来绘制多边形的。这个方法需要一个Pen对象来定义多边形的边界样式（颜色、宽度等），以及一个点数组Point[]来定义多边形的各个顶点。

正文

画一个五角星

C#
protected override void OnPaint(PaintEventArgs e)
{
    base.OnPaint(e);
    //申明一个黑色的画笔
    Pen pen = new Pen(Color.Black, 3);
    e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
    //为多边形顶点创建一个Point数组
    Point[] ps ={
               new Point(0,76),
               new Point(80,76),
               new Point(106,0),
               new Point(130,76),
               new Point(210,76),
               new Point(146,124),
               new Point(170,200),
               new Point(106,152),
               new Point(40,200),
               new Point(66,124),

               };
    e.Graphics.DrawPolygon(pen, ps);
}

画一个正方形

C#
protected override void OnPaint(PaintEventArgs e)
{
    base.OnPaint(e);
    Pen pen = new Pen(Color.Black, 3);
    e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
    Point[] ps ={
               new Point(10,10),
               new Point(10,100),
               new Point(100,100),
               new Point(100,10),
               };
    //连接多边形
    e.Graphics.DrawPolygon(pen, ps);
    //填充颜色
    e.Graphics.FillPolygon(new SolidBrush(Color.Red), ps);
}

调整Point顺序结果会不同

C#
protected override void OnPaint(PaintEventArgs e)
{
    base.OnPaint(e);
    Pen pen = new Pen(Color.Black, 3);
    e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
    Point[] ps ={
               new Point(10,10),
               new Point(100,100),
               new Point(10,100),
               new Point(100,10),
               };
    e.Graphics.DrawPolygon(pen, ps);
    e.Graphics.FillPolygon(new SolidBrush(Color.Red), ps);
}