如何在C#中利用GDI画树状图(非Treeview)

因项目需求，需要画出树状图，在网上搜了一下，发现这方面的资料是少之又少。没办法，只能自己摸索着做。下面给出一个简单的三层实例实现，权当抛砖引玉，以下是最终效果图：

首先需要说明的是树状图是在pictureBox控件下画的，代码写在其Paint事件下。

第一步，定义一下各个结点的内容以及结点数量等初始信息。这里就简单地直接赋值了，大多数情况下结点的内容应该从数据库中读取，这时只要对该部分的代码作相关修改即可。

[csharp]
string parentTree = "中国";
ArrayList midTree = new ArrayList();
midTree.Add("江苏省");
midTree.Add("山东省");
int midTreeCount = midTree.Count;
ArrayList subTree = new ArrayList();
subTree.Add("南京市");
subTree.Add("扬州市");
subTree.Add("苏州市");
subTree.Add("青岛市");
subTree.Add("日照市");
int subTreeCount = subTree.Count;
ArrayList eachSubTreeCount = new ArrayList();
eachSubTreeCount.Add(3);
eachSubTreeCount.Add(2);

定义一些画图需要的初始变量

[csharp]
int midCountFlag = 0;   //画中间结点时用到的偏移量
int subCountFlag = 0;   //画顶层结点时用到的偏移量
int x = 0;              //结点矩形图左上角X坐标
int y = 0;              //结点矩形图左上角Y坐标
int picX = pictureBox1.Width;   //绘图区域水平长度
int picY = pictureBox1.Height; //绘图区域竖直长度
StringFormat sf = new StringFormat();
sf.Alignment = StringAlignment.Center;
Rectangle rect;         //结点矩形图
Point loc;              //结点矩形图左上角坐标
Point startP;           //连接线起始坐标
Point endP;             //连接线终止坐标
Point tempP = new Point();   //坐标缓存量
SizeF sizeF;            //结点内容尺寸大小
Size s;
Font font = new Font("宋体", 18);     //结点内容的字体
Pen redPen = new Pen(Color.Red, 2);   //连线需要的画笔
Graphics g = e.Graphics;
g.Clear(Color.White);         //每次重绘先把绘图区域清空

OK，这时我们就可以开始画了，先把根部画出来。

[csharp]
#region 画树根
            sizeF = g.MeasureString(parentTree, font);
            sizeF.Width += 10;
            s = sizeF.ToSize();

            x = Convert.ToInt32((picX - sizeF.Width) / 2);
            y = 30;
            startP = new Point(picX / 2, y + s.Height);
            loc = new Point(x, y);

            rect = new Rectangle(loc, s);
            g.DrawRectangle(Pens.Black, rect);
            g.DrawString(parentTree, font, Brushes.Black, rect, sf);
#endregion

再把树根的子树画出来。

[csharp]
#region 画子树
            foreach (object o in midTree)
            {
                int picXMid = picX / midTreeCount;

                string strMidTree = o.ToString();
                sizeF = g.MeasureString(strMidTree, font);
                sizeF.Width += 10;
                s = sizeF.ToSize();

                x = Convert.ToInt32((picXMid - sizeF.Width) / 2 + picXMid * midCountFlag);
                y = 230;
                endP = new Point(picXMid / 2 + picXMid * midCountFlag, y);
                loc = new Point(x, y);

                rect = new Rectangle(loc, s);
                g.DrawRectangle(Pens.Black, rect);
                g.DrawString(strMidTree, font, Brushes.Black, rect, sf);
                g.DrawLine(redPen, startP, endP);

                midCountFlag++;
                if (midCountFlag == 1)
                    tempP = new Point(endP.X, endP.Y + s.Height);
            }
#endregion
画出子树的树枝。

[csharp]
#region 画子树的树枝

            startP = tempP;

            for (int i = 0; i != midTree.Count; ++i)
            {
                int picXMid = picX / midTreeCount;
                startP.X += picXMid * i;
                if (i >= 1)
                    subCountFlag += (int)eachSubTreeCount[i - 1];
                for (int j = 0; j != (int)eachSubTreeCount[i]; ++j)

补充：软件开发 , C# ,