asp.net下生成英文字符数字验证码的代码

时间:2021-10-04 14:25:43
代码如下:

using System; 
using System.Data; 
using System.Configuration; 
using System.Web; 
using System.Web.Security; 
using System.Web.UI; 
using System.Web.UI.WebControls; 
using System.Web.UI.WebControls.WebParts; 
using System.Web.UI.HtmlControls; 
using System.Drawing; 
using System.Drawing.Drawing2D; 

public partial class _Default : System.Web.UI.Page 

protected void Page_Load(object sender, EventArgs e) 


Bitmap bmp = new Bitmap(50, 25); 
Graphics g = Graphics.FromImage(bmp); 
SolidBrush sb = new SolidBrush(getColor()); 
g.DrawString(CheckNumber(), new Font("宋体", 16), sb, 0, 0); 
bmp.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Gif); 


public static string CheckNumber() 

string checkcode = "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; 
int len = 4; 
string tmpstr = ""; 
int iRandNum; 
Random rnd = new Random(); 
for (int i = 0; i < len; i++) 

iRandNum = rnd.Next(checkcode.Length); 
tmpstr += checkcode[iRandNum]; 

return tmpstr; 

private Color getColor() 

Random r = new Random(); 
return Color.FromArgb(r.Next(256), r.Next(256), r.Next(256)); 

}