GDI+绘制柱型图分析商品月销售情况
绘制柱型图分析商品月销售情况
柱型图也称为条形图，它是网站开发中最常用的一种图表技术之一。本节通过一个实例来介绍使用柱型图分析商品的月销售情况。实例运行结果如图1所示。
程序开发步骤如下所示。
（1）新建一个网站，命名为26_01，其主页默认为Default.aspx。
（2）在该网站中添加一个Info.aspx页面，该页面主要用来使用柱型图显示各月份的商品销售情况。
（3）程序主要代码如下。
Info.aspx页面中定义了两个方法，分别为sumNum方法和CreateImage方法，其中sumNum方法用来计算各月份的商品销售量总和，而CreateImage方法则用来调用Graphics对象的相关方法绘制柱型图。sumNum方法实现代码如下：
private int sumNum(int P_int_year)
{
string P_str_sum = "SELECT SUM(month1+month2+month3+month4+month5+month6+month7+month8+month9+ month10+month11+month12) AS number FROM tb_01 WHERE yearID=" + P_int_year + "";
SqlConnection sqlcon = new SqlConnection(ConfigurationManager.AppSettings["connectionString"]);
SqlDataAdapter myda = new SqlDataAdapter(P_str_sum, sqlcon);
DataSet myds = new DataSet();
myda.Fill(myds);
return Convert.ToInt32(myds.Tables[0].Rows[0][0].ToString());
}
CreateImage方法实现代码如下：
private void CreateImage(int P_int_year)
{
int height = 400, width = 600;
Bitmap image = new Bitmap(width, height);
//创建Graphics类对象
Graphics graphics = Graphics.FromImage(image);
try
{
//清空图片背景色
graphics.Clear(Color.White);
Font font = new Font("Arial", 9, FontStyle.Regular);
Font font1 = new Font("宋体", 20, FontStyle.Regular);
LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.Blue, 1.2f, True);
graphics.FillRectangle(Brushes.WhiteSmoke, 0, 0, width, height);
Brush brush1 = new SolidBrush(Color.Blue);
graphics.DrawString("" + P_int_year + "年商品月销售情况", font1, brush1, new PointF(150, 30));
//画图片的边框线
graphics.DrawRectangle(new Pen(Color.Blue), 0, 0, image.Width - 1, image.Height - 1);
Pen mypen = new Pen(brush, 1);
//绘制横向线条
int x = 100;
for (int i = 0; i < 11; i++)
{
graphics.DrawLine(mypen, x, 80, x, 366);
x = x + 40;
}
Pen mypen1 = new Pen(Color.Blue, 2);
graphics.DrawLine(mypen1, x - 480, 80, x - 480, 366);
//绘制纵向线条
int y = 106;
for (int i = 0; i < 10; i++)
{
graphics.DrawLine(mypen, 60, y, 540, y);
y = y + 26;
}
graphics.DrawLine(mypen1, 60, y, 540, y);
//x轴
String[] n = {" 一月", " 二月", " 三月", " 四月", " 五月", " 六月", " 七月",
" 八月", " 九月", " 十月", "十一月", "十二月"};
x = 60;
for (int i = 0; i < 12; i++)
{
graphics.DrawString(n[i].ToString(), font, Brushes.Red, x, 374); //设置文字内容及输出位置
x = x + 40;
}
//y轴
String[] m = {"100%", " 90%", " 80%", " 70%", " 60%", " 50%", " 40%", " 30%",
" 20%", " 10%", " 0%"};
y = 98;
for (int i = 0; i < 11; i++)
{
graphics.DrawString(m[i].ToString(), font, Brushes.Red, 25,y); //设置文字内容及输出位置
y = y + 26;
}
int[] Count = new int[12];
string P_str_yearID = "SELECT * FROM tb_01 WHERE yearID=" + P_int_year + "";
SqlConnection sqlcon = new SqlConnection(ConfigurationManager.AppSettings["connectionString"]);
SqlDataAdapter myda = new SqlDataAdapter(P_str_yearID, sqlcon);
DataSet myds = new DataSet();
myda.Fill(myds);
int P_int_num = sumNum(P_int_year);
for (int j = 0; j < 12; j++)
{
Count[j] = Convert.ToInt32(myds.Tables[0].Rows[0][j + 1].ToString()) * 100 / P_int_num;
}
//显示柱状效果
x = 70;
for (int i = 0; i < 12; i++)
{
SolidBrush mybrush = new SolidBrush(Color.Red);
graphics.FillRectangle(mybrush, x, 366 - Count[i] * 26 / 10, 20, Count[i] * 26 / 10);
x = x + 40;
}
System.IO.MemoryStream MStream = new System.IO.MemoryStream();
image.Save(MStream, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(MStream.ToArray());
}
finally
