NET 很简单的一个生成随机验证码封装的一个类

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;

/// <summary>

/// VerifyCode 的摘要说明 产生随机数

/// </summary>

public class VerifyCode

{

public VerifyCode()

{

}

//产生随机字符串

/// <summary>

/// 产生随机数

/// </summary>

/// <param name="num">需要的字符的个数</param>

/// <returns>返回产生的随机数</returns>

public string GenCode(int num)

{

//定义一个数组

string[] source ={"0","1","2","3","4","5","6","7","8","9",

"A","B","C","D","E","F","G","H","I","J","K","L","M","N",

"O","P","Q","R","S","T","U","V","W","X","Y","Z"};

//定义一个装数组的字符串

string code = "";

Random rd = new Random();

for (int i = 0; i < num; i++)

{

code += source[rd.Next(0, source.Length)];

}

return code;//返回产生的随机数

}

//生成图片

public void GenImg(string code, Page curPage)

{

Bitmap myPalette = new Bitmap(60, 20);//定义一个画板

Graphics gh = Graphics.FromImage(myPalette);//在画板上定义绘图的实例

Rectangle rc = new Rectangle(0, 0, 60, 20);//定义一个矩形

gh.FillRectangle(new SolidBrush(Color.Blue), rc);//填充矩形

gh.DrawString(code, new Font("宋体", 16), new SolidBrush(Color.White), rc);//在矩形内画出字符串

myPalette.Save(curPage.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);//将图片显示出来

curPage.Session["ValidateCode"] = code;//将字符串保存到Session中，以便需要时进行验证

gh.Dispose();//关闭　

myPalette.Dispose();

}

}