3种验证码示例(代码)(数字,数字字母混和,汉字)

Default.aspx

<table>

<tr>

<td class="style1">

 (验证码测试)</td>

<td>

  <asp:Label

ID="Label1" runat="server"></asp:Label>

<asp:Image ID="Image1" runat="server" Height="22px" ImageUrl="~/ValidNums.aspx" Width="58px" /> 

<asp:Image ID="Image2" runat="server" Height="22px" ImageUrl="~/GetValid.aspx" Width="58px" /></td>

</tr><tr>

<td class="style1">

</td>

<td>

  <asp:Button ID="Button1" runat="server" Text="登录" OnClick="btnOK_Click" />

<asp:Button ID="Button2" runat="server" Text="取消" />

</td>

</tr>

</table>

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

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

{

 protected void Page_Load(object sender, EventArgs e)

{

 if (!Page.IsPostBack)

{

 string getNums = GetVali();

 Label1.Text = getNums;

}

}

 /// <summary>

 /// 随机生成4位数

 /// </summary>

 /// <returns>返回生成的随机数</returns>

 public string GetVali()

{

 string strsvali = "0,1,2,3,4,5,6,7,8,9";

 string[] ValiArray = strsvali.Split(',');

 string ReturnNum = "";

 int nums = -1;

 Random vrand = new Random();

 for (int n = 1; n < 5; n++)

{

 if (nums != -1)

{

 vrand = new Random(n * nums * unchecked((int)DateTime.Now.Ticks));

}

 int t = vrand.Next(10);

 nums = t;

 ReturnNum += ValiArray[t];

}

 Session["Valid"] = ReturnNum;

 return ReturnNum;

}

 protected void btnOK_Click(object sender, EventArgs e)

{

 if (Session["Valid"].ToString() == TextBox3.Text)

{ 

 ClientScript.RegisterStartupScript(this.GetType(),"ss","<script>alert('您已经成功通过登录验证！')</script>");

}

 else

{

 ClientScript.RegisterStartupScript(this.GetType(), "ss", "<script>alert('您输入的验证码错误！')</script>");

}

}

}

GetValid.aspx

(可以直接将该页面作为源赋值给ImageUrl)

前台为空，后台代码如下：

using System;

using System.Collections;

using System.Configuration;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using System.Text;

using System.Drawing;

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

{

 protected void Page_Load(object sender, EventArgs e)

{

 if (!IsPostBack)

{

 string validateNum = GetValids(); //成生4位随机字符串

 CreateImage(validateNum); //将生成的随机字符串绘成图片

 Session["ValidNums"] = validateNum; //保存验证码

}

}

 public staticstring GetValids()

{

 //获取GB2312编码页（表） 

 Encoding gb = Encoding.GetEncoding("gb2312");

 //调用函数产生4个随机中文汉字编码 

 object[] bytes = CreateRegionCode(4);

 //根据汉字编码的字节数组解码出中文汉字 

 string s = String.Empty;

 foreach (object byt in bytes)

{

 string str1 = gb.GetString((byte[])Convert.ChangeType(byt, typeof(byte[])));

 s = s + str1;

}

 //输出的控制台 

 return s;

}

 public static object[] CreateRegionCode(int strlength)

{

 //定义一个字符串数组储存汉字编码的组成元素 

 string[] rBase = new String[16]{ "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};

 Random rnd = new Random();

 //定义一个object数组用来 

 object[] bytes = new object[strlength];

 /*每循环一次产生一个含两个元素的十六进制字节数组，并将其放入bject数组中 

每个汉字有四个区位码组成 

 区位码第1位和区位码第2位作为字节数组第一个元素 

 区位码第3位和区位码第4位作为字节数组第二个元素 

*/

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

{

 //区位码第1位 

 int r1 = rnd.Next(11, 14);

 string str_r1 = rBase[r1].Trim();

 //区位码第2位 

 rnd = new Random(r1 * unchecked((int)DateTime.Now.Ticks) + i);

 //更换随机数发生器的种子避免产生重复值 

 int r2;

 if (r1 == 13)

{

 r2 = rnd.Next(0, 8);

}

 else

{

 r2 = rnd.Next(0, 16);

}

 string str_r2 = rBase[r2].Trim();

 //区位码第3位 

 rnd = new Random(r2 * unchecked((int)DateTime.Now.Ticks) + i);

 int r3 = rnd.Next(10, 16);

 string str_r3 = rBase[r3].Trim();

 //区位码第4位 

 rnd = new Random(r3 * unchecked((int)DateTime.Now.Ticks) + i);

 int r4;

 if (r3 == 10)

{

 r4 = rnd.Next(1, 16);

}

 else if (r3 == 15)

{

 r4 = rnd.Next(0, 15);

}

 else

{

 r4 = rnd.Next(0, 16);

}

 string str_r4 = rBase[r4].Trim();

 //定义两个字节变量存储产生的随机汉字区位码 

 byte byte1 = Convert.ToByte(str_r1 + str_r2, 16);

 byte byte2 = Convert.ToByte(str_r3 + str_r4, 16);

 //将两个字节变量存储在字节数组中 

 byte[] str_r = new byte[]{ byte1, byte2};

 //将产生的一个汉字的字节数组放入object数组中 

 bytes.SetValue(str_r, i);

}

 return bytes;

}

 //生成图片

 private void CreateImage(string validateNum)

{

 if (validateNum == null || validateNum.Trim() == String.Empty)

 return;

 //生成Bitmap图像

 System.Drawing.Bitmap image = new System.Drawing.Bitmap(validateNum.Length * 12 + 10, 22);

 Graphics g = Graphics.FromImage(image);

 try

{

 //生成随机生成器 

 Random random = new Random();

 //清空图片背景色 

 g.Clear(Color.White);

 //画图片的背景噪音线 

 for (int i = 0; i < 25; i++)

{

 int x1 = random.Next(image.Width);

 int x2 = random.Next(image.Width);

 int y1 = random.Next(image.Height);

 int y2 = random.Next(image.Height);

 g.DrawLine(new Pen(Color.Coral), x1, y1, x2, y2);

}

 Font font = new System.Drawing.Font("Arial", 8);

 System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);

 g.DrawString(validateNum, font, brush, 2, 2);

 //画图片的前景噪音点 

 for (int i = 0; i < 100; i++)

{

 int x = random.Next(image.Width);

 int y = random.Next(image.Height);

 image.SetPixel(x, y, Color.FromArgb(random.Next()));

}

 //画图片的边框线 

 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

 System.IO.MemoryStream ms = new System.IO.MemoryStream();

 //将图像保存到指定的流

 image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);

 Response.ClearContent();

 Response.ContentType = "image/Gif";

 Response.BinaryWrite(ms.ToArray());

}

 finally

{

 g.Dispose();

 image.Dispose();

}

}

}

ValidNums.aspx

(可以直接将该页面作为源赋值给ImageUrl)

前台为空，后台代码如下：

using System;

using System.Collections;

using System.Configuration;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using System.Drawing;

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

{

 protected void Page_Load(object sender, EventArgs e)

{

 if (!IsPostBack)

{

 string validateNum = CreateRandomNum(4);//成生4位随机字符串

 CreateImage(validateNum); //将生成的随机字符串绘成图片

 Session["ValidNums"] = validateNum; //保存验证码

}

}

 //生成随机字符串

 private string CreateRandomNum(int NumCount)

{

 string allChar = "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,W,X,Y,Z";

 string[] allCharArray = allChar.Split(',');//拆分成数组

 string randomNum = "";

 int temp = -1;//记录上次随机数的数值，尽量避免产生几个相同的随机数

 Random rand = new Random();

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

{

 if (temp != -1)

{

 rand = new Random(i * temp * ((int)DateTime.Now.Ticks));

}

 int t = rand.Next(35);

 if (temp == t)

{

 return CreateRandomNum(NumCount);

}

 temp = t;

 randomNum += allCharArray[t];

}

 return randomNum;

}

 //生成图片

 private void CreateImage(string validateNum)

{

 if (validateNum == null || validateNum.Trim() == String.Empty)

 return;

 //生成Bitmap图像

 System.Drawing.Bitmap image = new System.Drawing.Bitmap(validateNum.Length * 12 + 10, 22);

 Graphics g = Graphics.FromImage(image);

 try

{

 //生成随机生成器 

 Random random = new Random();

 //清空图片背景色 

 g.Clear(Color.White);

 //画图片的背景噪音线 

 for (int i = 0; i < 25; i++)

{

 int x1 = random.Next(image.Width);

 int x2 = random.Next(image.Width);

 int y1 = random.Next(image.Height);

 int y2 = random.Next(image.Height);

 g.DrawLine(new Pen(Color.Coral), x1, y1, x2, y2);

}

 Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));

 System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);

 g.DrawString(validateNum, font, brush, 2, 2);

 //画图片的前景噪音点 

 for (int i = 0; i < 100; i++)

{

 int x = random.Next(image.Width);

 int y = random.Next(image.Height);

 image.SetPixel(x, y, Color.FromArgb(random.Next()));

}

 //画图片的边框线 

 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

 System.IO.MemoryStream ms = new System.IO.MemoryStream();

 //将图像保存到指定的流

 image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);

 Response.ClearContent();

 Response.ContentType = "image/Gif";

 Response.BinaryWrite(ms.ToArray());

}

 finally

{

 g.Dispose();

 image.Dispose();

}

}

}

以上是3种验证码的全部代码。

另外也可以使用ashx请求验证码的方式，本示例仅使用Session存值处理。