asp.net中3种验证码示例(实现代码)(数字,数字字母混和,汉字)

<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)datetiR_212_11845@e.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(),"<script>alert('您输入的验证码错误！')</script>");
}
}
}

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 static String 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)datetiR_212_11845@e.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)datetiR_212_11845@e.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)datetiR_212_11845@e.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,image.Width,image.Height),Color.blue,Color.DarkRed,1.2f,truE);
g.DrawString(validateNum,font,brush,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),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();
}
}
}

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 = "0,9,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)datetiR_212_11845@e.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 + 10,12,(System.Drawing.FontStyle.bold | System.Drawing.FontStyle.ItaliC));
System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0,System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.binaryWrite(ms.ToArray());
}
finally
{
g.Dispose();
image.Dispose();
}
}
}