C# 绘制统计图(柱状图, 折线图, 扇形图)

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统计图形种类繁多, 有柱状图, 折线图, 扇形图等等, 而统计图形的绘制方法也有很多, 有Flash制作的统计图形, 有水晶报表生成统计图形, 有专门制图软件制作, 也有编程语言自己制作的；这里我们用就C# 制作三款最经典的统计图: 柱状图, 折线图和扇形图；既然是统计, 当然需要数据, 这里演示的数据存于Sql Server2000中, 三款统计图形都是动态生成. 其中柱状图我会附上制作步骤, 其他两款统计图直接附源码.

说明: 需求不一样, 统计图形绘制后的显示效果也不一样, 比如这里柱状图的主要需求是为了比较每一期报名人数与通过人数的差, 因此会把两根柱子放在一起会使比较结果一目了然. 因此大家可以根据需要灵活绘制.

一. 柱状图的绘制.

绘制步骤如下:

1. 定义绘图用到的类.

定义绘图类

2. 绘制图框.

绘制图框

3. 绘制横向坐标线

绘制横向坐标线

4. 绘制纵向坐标线

绘制纵向坐标线

5. 绘制横坐标值

绘制横坐标值

6. 绘制纵坐标值

绘制纵坐标

7. 定义数组存储数据库中统计的数据

定义存储统计数据的数组

8. 从数据库中读取报名人数与通过人数

读取数据

9. 将读取的数据存储到数组中

将数据存储到数组中

10.定义画笔和画刷准备绘图

准备绘制柱状图

11. 根据数组中的值绘制柱状图

绘制柱状图

12. 将图形输出到页面.

将页面输出到页中

最终柱状图的效果图:

柱状图的完整代码:

绘制柱状统计图的完整代码

二. 折线统计图的绘制

效果:

折线图的完整代码:

private void CreateImage()
{
int height = 480, width = 700;
Bitmap image = new Bitmap(width, height);
Graphics g = Graphics.FromImage(image);

try
{
//清空图片背景色
g.Clear(Color.White);

Font font = new System.Drawing.Font("Arial", 9, FontStyle.Regular);
Font font1 = new System.Drawing.Font("宋体", 20, FontStyle.Regular);
Font font2 = new System.Drawing.Font("Arial", 8, FontStyle.Regular);
LinearGradientBrush brush = new LinearGradientBrush(
new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.Blue, 1.2f, true);
g.FillRectangle(Brushes.AliceBlue, 0, 0, width, height);
Brush brush1 = new SolidBrush(Color.Blue);
Brush brush2 = new SolidBrush(Color.SaddleBrown);

g.DrawString(this.ddlTaget.SelectedItem.Text + " " + this.ddlYear.SelectedItem.Text +
" 成绩统计折线图", font1, brush1, new PointF(85, 30));
//画图片的边框线
g.DrawRectangle(new Pen(Color.Blue), 0, 0, image.Width - 1, image.Height - 1);

Pen mypen = new Pen(brush, 1);
Pen mypen2 = new Pen(Color.Red, 2);
//绘制线条
//绘制纵向线条
int x = 60;
for (int i = 0; i < 8; i++)
{
g.DrawLine(mypen, x, 80, x, 340);
x = x + 80;
}
Pen mypen1 = new Pen(Color.Blue, 3);
x = 60;
g.DrawLine(mypen1, x, 82, x, 340);

//绘制横向线条
int y = 106;
for (int i = 0; i < 10; i++)
{
g.DrawLine(mypen, 60, y, 620, y);
y = y + 26;
}
// y = 106;
g.DrawLine(mypen1, 60, y - 26, 620, y - 26);

//x轴
String[] n = { "第一期", "第二期", "第三期", "第四期", "上半年", "下半年", "全年统计" };
x = 45;
for (int i = 0; i < 7; i++)
{
g.DrawString(n[i].ToString(), font, Brushes.Red, x, 348); //设置文字内容及输出位置
x = x + 77;
}

//y轴
String[] m = { "220人", " 200人", " 175人", "150人", " 125人", " 100人", " 75人", " 50人",
" 25人"};
y = 100;
for (int i = 0; i < 9; i++)
{
g.DrawString(m[i].ToString(), font, Brushes.Red, 10, y); //设置文字内容及输出位置
y = y + 26;
}

int[] Count1 = new int[7];
int[] Count2 = new int[7];

SqlConnection Con = new SqlConnection("Server=(Local);Database=committeeTraining;Uid=sa;Pwd=eesoft");
Con.Open();
string cmdtxt2 = "SELECT * FROM ##Count where Company='" + this.ddlTaget.SelectedItem.Text.Trim() + "'";
SqlDataAdapter da = new SqlDataAdapter(cmdtxt2, Con);
DataSet ds = new DataSet();
da.Fill(ds);

//报名人数
Count1[0] = Convert.ToInt32(ds.Tables[0].Rows[0]["count1"].ToString());
Count1[1] = Convert.ToInt32(ds.Tables[0].Rows[0]["count3"].ToString());
Count1[2] = Convert.ToInt32(ds.Tables[0].Rows[0]["count5"].ToString());
Count1[3] = Convert.ToInt32(ds.Tables[0].Rows[0]["count7"].ToString());

Count1[6] = Convert.ToInt32(ds.Tables[0].Rows[0]["count9"].ToString()); //全年

Count1[4] = Count1[0] + Count1[1];
Count1[5] = Count1[2] + Count1[3];

Count2[0] = Convert.ToInt32(ds.Tables[0].Rows[0]["count2"].ToString());
Count2[1] = Convert.ToInt32(ds.Tables[0].Rows[0]["count4"].ToString());
Count2[2] = Convert.ToInt32(ds.Tables[0].Rows[0]["count6"].ToString());
Count2[3] = Convert.ToInt32(ds.Tables[0].Rows[0]["count8"].ToString());

Count2[6] = Convert.ToInt32(ds.Tables[0].Rows[0]["count10"].ToString()); //全年

Count2[4] = Count2[0] + Count2[1];
Count2[5] = Count2[2] + Count2[3];

//显示折线效果
Font font3 = new System.Drawing.Font("Arial", 10, FontStyle.Bold);
SolidBrush mybrush = new SolidBrush(Color.Red);
Point[] points1 = new Point[7];
points1[0].X = 60; points1[0].Y = 340 - Count1[0]; //从106纵坐标开始, 到(0, 0)坐标时
points1[1].X = 140; points1[1].Y = 340 - Count1[1];
points1[2].X = 220; points1[2].Y = 340 - Count1[2];
points1[3].X = 300; points1[3].Y = 340 - Count1[3];

points1[4].X = 380; points1[4].Y = 340 - Count1[4];
points1[5].X = 460; points1[5].Y = 340 - Count1[5];

points1[6].X = 540; points1[6].Y = 340 - Count1[6];
g.DrawLines(mypen2, points1); //绘制折线

//绘制数字
g.DrawString(Count1[0].ToString(), font3, Brushes.Red, 58, points1[0].Y - 20);
g.DrawString(Count1[1].ToString(), font3, Brushes.Red, 138, points1[1].Y - 20);
g.DrawString(Count1[2].ToString(), font3, Brushes.Red, 218, points1[2].Y - 20);
g.DrawString(Count1[3].ToString(), font3, Brushes.Red, 298, points1[3].Y - 20);

g.DrawString(Count1[4].ToString(), font3, Brushes.Red, 378, points1[4].Y - 20);
g.DrawString(Count1[5].ToString(), font3, Brushes.Red, 458, points1[5].Y - 20);

g.DrawString(Count1[6].ToString(), font3, Brushes.Red, 538, points1[6].Y - 20);

Pen mypen3 = new Pen(Color.Green, 2);
Point[] points2 = new Point[7];
points2[0].X = 60; points2[0].Y = 340 - Count2[0];
points2[1].X = 140; points2[1].Y = 340 - Count2[1];
points2[2].X = 220; points2[2].Y = 340 - Count2[2];
points2[3].X = 300; points2[3].Y = 340 - Count2[3];

points2[4].X = 380; points2[4].Y = 340 - Count2[4];
points2[5].X = 460; points2[5].Y = 340 - Count2[5];

points2[6].X = 540; points2[6].Y = 340 - Count2[6];
g.DrawLines(mypen3, points2); //绘制折线

//绘制通过人数
g.DrawString(Count2[0].ToString(), font3, Brushes.Green, 61, points2[0].Y - 15);
g.DrawString(Count2[1].ToString(), font3, Brushes.Green, 131, points2[1].Y - 15);
g.DrawString(Count2[2].ToString(), font3, Brushes.Green, 221, points2[2].Y - 15);
g.DrawString(Count2[3].ToString(), font3, Brushes.Green, 301, points2[3].Y - 15);

g.DrawString(Count2[4].ToString(), font3, Brushes.Green, 381, points2[4].Y - 15);
g.DrawString(Count2[5].ToString(), font3, Brushes.Green, 461, points2[5].Y - 15);

g.DrawString(Count2[6].ToString(), font3, Brushes.Green, 541, points2[6].Y - 15);

//绘制标识
g.DrawRectangle(new Pen(Brushes.Red), 180, 390, 250, 50); //绘制范围框
g.FillRectangle(Brushes.Red, 270, 402, 20, 10); //绘制小矩形
g.DrawString("报名人数", font2, Brushes.Red, 292, 400);

g.FillRectangle(Brushes.Green, 270, 422, 20, 10);
g.DrawString("通过人数", font2, Brushes.Green, 292, 420);

System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
Response.ClearContent();
Response.ContentType = "image/Jpeg";
Response.BinaryWrite(ms.ToArray());
}
finally
{
g.Dispose();
image.Dispose();
}
}

三. 扇形统计图的绘制

效果图:

完整代码:

扇形统计图的绘制