常用的產生驗證碼程式 ，圖片效果如下：
來源程式如下：
複製代碼 代碼如下:using System;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using System.Text;
using System.Collections;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
/**//// <summary>
///
/// ** asp.net(C#) 產生驗證碼 **
///
/// File: GenerateCheckCode.aspx.cs
///
/// Author: 周振興 (Zxjay 飄遙)
///
/// E-Mail: tda7264@163.com
///
/// Date: 07-04-10
///
/// </summary>
public partial class GenerateCheckCode : System.Web.UI.Page
...{
protected void Page_Load(object sender, EventArgs e)
...{
string chkCode = string.Empty;
//顏色列表，用於驗證碼、噪線、噪點
Color[] color =...{ Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue };
//字型列表，用於驗證碼
string[] font =...{ "Times New Roman", "MS Mincho", "Book Antiqua", "Gungsuh", "PMingLiU", "Impact" };
//驗證碼的字元集，去掉了一些容易混淆的字元
char[] character =...{ '2', '3', '4', '5', '6', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };
Random rnd = new Random();
//產生驗證碼字串
for (int i = 0; i < 4; i++)
...{
chkCode += character[rnd.Next(character.Length)];
}
Bitmap bmp = new Bitmap(100, 40);
Graphics g = Graphics.FromImage(bmp);
g.Clear(Color.White);
//畫噪線
for (int i = 0; i < 10; i++)
...{
int x1 = rnd.Next(100);
int y1 = rnd.Next(40);
int x2 = rnd.Next(100);
int y2 = rnd.Next(40);
Color clr = color[rnd.Next(color.Length)];
g.DrawLine(new Pen(clr), x1, y1, x2, y2);
}
//畫驗證碼字串
for (int i = 0; i < chkCode.Length; i++)
...{
string fnt = font[rnd.Next(font.Length)];
Font ft = new Font(fnt, 18);
Color clr = color[rnd.Next(color.Length)];
g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * 20 + 8, (float)8);
}
//畫噪點
for (int i = 0; i < 100; i++)
...{
int x = rnd.Next(bmp.Width);
int y = rnd.Next(bmp.Height);
Color clr = color[rnd.Next(color.Length)];
bmp.SetPixel(x, y, clr);
}
//清除該頁輸出緩衝，設定該頁無緩衝
Response.Buffer = true;
Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
Response.Expires = 0;
Response.CacheControl = "no-cache";
Response.AppendHeader("Pragma", "No-Cache");
//將驗證碼圖片寫入記憶體流，並將其以 "image/Png" 格式輸出
MemoryStream ms = new MemoryStream();
try
...{
bmp.Save(ms, ImageFormat.Png);
Response.ClearContent();
Response.ContentType = "image/Png";
Response.BinaryWrite(ms.ToArray());
}
finally
...{
//顯式釋放資源
bmp.Dispose();
g.Dispose();
}
}
}
使用方法如下：
建立名為 GenerateCheckCode.aspx 的檔案，將上述代碼拷貝到代碼檔案 GenerateCheckCode.aspx.cs
在需要驗證碼的地方放置語句 <asp:Image ID="img1" runat="server" ImageUrl="~/GenerateCheckCode.aspx" /> 即可。
