C#绘制曲线图和柱状图

在我们程序开发的过程中经常会需要绘制曲线图和柱状图等，尤其是在做统计功能时。但是有时候我们有觉得没有必要使用第三方控件（例如：ZedGraph等），这是我们可以自己编写代码来实现这些图形绘制的功能。以下是我在开发过程中所使用过的两段代码，现共享大家，希望能给大家带来一定的帮助，如有不妥敬请斧正！
1.柱状图，效果图如下

代码如下：

注意：请注意参数 chartTable 图形里的一些元素需要从chartTable里面取。具体请查看代码。

1.         //Render是图形大标题，图开小标题，图形宽度，图形长度，饼图的数据集和饼图的数据集 
2.         public Image Render(string title, int width, int height, DataTable chartTable)
3.         {
4.             Bitmap bm = new Bitmap(width, height);
5.             Graphics g = Graphics.FromImage(bm);
6.             g.Clear(Color.White);
8.             DataTable dt = chartTable;
9.             const int top = 30;
10.             const int left = 35;
12.             if (width < left * 2 || height < top * 2)
13.             {
14.                 g.DrawString("绘图区域太小", new Font("Tahoma", 8),
15.                     Brushes.Blue, new PointF(0, 0));
16.                 return bm;
17.             }
19.             //计算最高的点 
20.             float highPoint = 1;
21.             foreach (DataRow dr in dt.Rows)
22.             {
23.                if (highPoint < Convert.ToSingle(dr[0]))
24.                 {
25.                     highPoint = Convert.ToSingle(dr[0]);
26.                 }
28.                 if (highPoint < Convert.ToSingle(dr[1]))
29.                 {
30.                     highPoint = Convert.ToSingle(dr[1]);
31.                 }
32.             }
33.             try
34.             {
35.                 //画大标题 
36.                 g.DrawString(title, new Font("Tahoma", 12), Brushes.Black, new PointF(2, 2));
37.                 StringFormat drawFormat = new StringFormat();
38.                 drawFormat.FormatFlags = StringFormatFlags.DirectionVertical;
40.                 g.DrawString("[红--" + dt.Columns[0].ToString() + "]", new Font("Tahoma", 8),
41.                     Brushes.Red, new PointF(2, top), drawFormat);
42.                 g.DrawString("[蓝--" + dt.Columns[1].ToString() + "]", new Font("Tahoma", 8),
43.                     Brushes.Blue, new PointF(17, top), drawFormat);
45.                 //画条形图 
46.                 float barWidth = (Convert.ToSingle(width) - left) / (dt.Rows.Count * 3 + 1);
47.                 PointF barOrigin = new PointF(left + barWidth, 0);
48.                 float barHeight = dt.Rows.Count;
49.                 float topFontSize = (barWidth / highPoint.ToString().Length);
50.                 
51.                 if (topFontSize > 2*top/3)
52.                 {
53.                     topFontSize = 2*top/3;
54.                 }
55.                 if (topFontSize < 5)
56.                 {
57.                     topFontSize = 5;
58.                 }
59.                 for (int i = 0; i < dt.Rows.Count; i++)
60.                 {
61.                     //底部字体的大小
62.                     float bottomFontSize = (2 * barWidth / dt.Rows[i][2].ToString().Length) + 2;
63.                     if (bottomFontSize > 2 * top / 3)
64.                     {
65.                         bottomFontSize = 2 * top / 3;
66.                     }
68.                     barHeight = Convert.ToSingle(dt.Rows[i][0]) * (height - 2 * top) / highPoint * 1;
69.                     barOrigin.Y = height - barHeight - top;
70.                     g.FillRectangle(new SolidBrush(Color.Red), barOrigin.X, barOrigin.Y, barWidth, barHeight);
71.                     //柱状图底部
72.                     g.DrawString(dt.Rows[i][2].ToString(), new Font("Tahoma", bottomFontSize), Brushes.Black,
73.                         new PointF(barOrigin.X, height - top));
74.                     //柱状图顶部
75.                     g.DrawString(dt.Rows[i][0].ToString(), new Font("Tahoma", topFontSize), Brushes.Red,
76.                         new PointF(barOrigin.X, barOrigin.Y - 3*topFontSize/2));
78.                     barOrigin.X = barOrigin.X + barWidth;
81.                     barHeight = Convert.ToSingle(dt.Rows[i][1]) * (height - 2 * top) / highPoint * 1;
82.                     barOrigin.Y = height - barHeight - top;
83.                     g.FillRectangle(new SolidBrush(Color.Blue), barOrigin.X, barOrigin.Y, barWidth, 
85. barHeight);
86.                     //柱状图顶部
87.                     g.DrawString(dt.Rows[i][1].ToString(), new Font("Tahoma", topFontSize), Brushes.Blue,
88.                         new PointF(barOrigin.X, barOrigin.Y - 3 * topFontSize/2));
89.                     barOrigin.X = barOrigin.X + (barWidth * 2);
90.                 }
92.                 //设置边 
93.                 g.DrawLine(new Pen(Color.Blue, 2), new Point(left, top),
94.                     new Point(left, height - top));
96.                 g.DrawLine(new Pen(Color.Blue, 2), new Point(left, height - top),
97.                     new Point(left + width, height - top));
99.                 g.Dispose();
100.                 return bm;
101.             }
102.             catch
103.             {
104.                 return bm;
105.             }
106.         }

2.线状图，效果如下：

代码如下：

注意：请注意参数 chartTable 图形里的一些元素需要从chartTable里面取。具体请查看代码。

1.         //Render是图形大标题，图开小标题，图形宽度，图形长度，饼图的数据集和饼图的数据集 
2.         public Image Render(string title, int width, int height, DataTable chartTable)
3.         {
4.             Bitmap bm = new Bitmap(width, height);
5.             Graphics g = Graphics.FromImage(bm);
6.             g.Clear(Color.White);
8.             const int top = 30;
9.             const int left = 35;
10.             if (width < left * 2 || height < top * 2)
11.             {
12.                 g.DrawString("绘图区域太小" ,new Font("Tahoma", 8),
13.                     Brushes.Blue, new PointF(0, 0));
14.                 return bm;
15.             }
17.             if (chartTable == null)
18.             {
19.                 g.DrawString("没有数据", new Font("Tahoma", 7),
20.                     Brushes.Blue, new PointF(0, 0));
21.                 return bm;
22.             }
24.             DataTable dt = chartTable;
26.             //计算最高的点 
27.             float highPoint = 1;
28.             foreach (DataRow dr in dt.Rows)
29.             {
30.                 if (highPoint < Convert.ToSingle(dr[0]))
31.                 {
32.                     highPoint = Convert.ToSingle(dr[0]);
33.                 }
35.                 if (highPoint < Convert.ToSingle(dr[1]))
36.                 {
37.                     highPoint = Convert.ToSingle(dr[1]);
38.                 }
39.             }
41.             //建立一个Graphics对象实例 
42.             try
43.             {
44.                 //画大标题 
45.                 g.DrawString(title, new Font("Tahoma", 12), Brushes.Black, new PointF(2, 2));
46.                 StringFormat drawFormat = new StringFormat();
47.                 drawFormat.FormatFlags = StringFormatFlags.DirectionVertical;
49.                 g.DrawString("[红--" + dt.Columns[0].ToString() + "]", new Font("Tahoma", 8),
50.                     Brushes.Red, new PointF(2, top), drawFormat);
51.                 g.DrawString("[蓝--" + dt.Columns[1].ToString() + "]", new Font("Tahoma", 8),
52.                     Brushes.Blue, new PointF(17, top), drawFormat);
54.                 //画条形图 
55.                 float barWidth = (Convert.ToSingle(width) - left) / (dt.Rows.Count + 1);
56.                 PointF barOrigin = new PointF(left + barWidth , 0);
57.                 float barHeight = dt.Rows.Count;
58.                 float topFontSize = 7;
59.                 float bottomFontSize = 7;
61.                 PointF[] pt1 = new PointF[dt.Rows.Count];
62.                 PointF[] pt2 = new PointF[dt.Rows.Count];
64.                 for (int i = 0; i < dt.Rows.Count; i++)
65.                 {
66.                     //底部字体的大小
67.                     barHeight = Convert.ToSingle(dt.Rows[i][0]) * (height - 2 * top) / highPoint * 1;
68.                     barOrigin.Y = height - barHeight - top;
69.                     g.FillEllipse(new SolidBrush(Color.Red), barOrigin.X - 3, barOrigin.Y - 3, 6, 6);
70.                     pt1[i] = new PointF(barOrigin.X, barOrigin.Y);
71.                     //顶部
72.                     g.DrawString(dt.Rows[i][0].ToString(), new Font("Tahoma", topFontSize), Brushes.Red,
73.                         new PointF(barOrigin.X, barOrigin.Y - 4 * topFontSize / 2));
75.                     barHeight = Convert.ToSingle(dt.Rows[i][1]) * (height - 2 * top) / highPoint * 1;
76.                     barOrigin.Y = height - barHeight - top;
77.                     g.FillEllipse(new SolidBrush(Color.Blue), barOrigin.X - 3, barOrigin.Y - 3, 6, 6);
78.                     pt2[i] = new PointF(barOrigin.X, barOrigin.Y);
79.                     //顶部
80.                     g.DrawString(dt.Rows[i][1].ToString(), new Font("Tahoma", topFontSize), Brushes.Blue,
81.                         new PointF(barOrigin.X, barOrigin.Y - 4 * topFontSize / 2));
82.                     barOrigin.X = barOrigin.X + barWidth;
83.                 }
84.                 if (dt.Rows.Count > 10)
85.                 {
86.                     int dis = dt.Rows.Count / 10;
87.                     for (int i = 0; i < dt.Rows.Count; i++)
88.                     {
89.                         if (i % dis == 0)
90.                         {
91.                             g.DrawLine(new Pen(Color.Blue, 2), new PointF(left + (i + 1) * barWidth, height - 
93. top + 5),
94.                                 new PointF(left + (i + 1) * barWidth, height - top - 3));
95.                             //底部
96.                             g.DrawString(dt.Rows[i][2].ToString(), new Font("Tahoma", bottomFontSize), 
98. Brushes.Black,
99.                                 new PointF(left + (i + 1) * barWidth, height - top));
100.                         }
101.                         else
102.                         {
103.                             g.DrawLine(new Pen(Color.Gray, 1), new PointF(left + (i+1) * barWidth, height - 
105. top + 3),
106.                                 new PointF(left + (i+1) * barWidth, height - top - 3));
107.                         }
108.                     }
109.                 }
110.                 else
111.                 {
112.                     for (int i = 0; i < dt.Rows.Count; i++)
113.                     {
114.                         g.DrawLine(new Pen(Color.Gray, 1), new PointF(left + (i + 1) * barWidth, height - top 
116. + 3),
117.                             new PointF(left + (i + 1) * barWidth, height - top - 3));
118.                     }
119.                 }
121.                 //绘制曲线
122.                 g.DrawLines(new Pen(new SolidBrush(Color.Red), 1), pt1);
123.                 g.DrawLines(new Pen(new SolidBrush(Color.Blue),1), pt2);
124.                 //设置边 
125.                 g.DrawLine(new Pen(Color.Blue, 2), new Point(left, top),
126.                     new Point(left, height - top));
127.                 g.DrawLine(new Pen(Color.Blue, 2), new Point(left, height - top),
128.                     new Point(left + width, height - top));
130.                 g.Dispose();
131.                 return bm;
132.             }
133.             catch
134.             {
135.                 return bm;
136.             }
137.         }

补充一句：转载的朋友请一定注明出处谢谢！半支烟阿杰
http://blog.csdn.net/gisfarmer/