asp.net登录验证码实现方法

前端添加的标签和方法：
验证码：

复制代码 代码如下:

   点击图片刷新

//标签

$(function () {
      $("#imgValidateCode").click(function () {
        DoFresh();
      });
      DoFresh();
    })
function DoFresh() {
      var img = $("#imgValidateCode");
      img.attr("src", "VerifyCode.aspx?random=" + Math.random());

    } //添加的方法，src是生成图片的aspx的地址 

然后在项目中在新建一个VerifyCode.aspx，下面是aspx的代码：

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="VerifyCode.aspx.cs" Inherits="Form.VerifyCode" %> 


 

   

 
 
   

   

   
  
   

 
  

接着是aspx.cs的代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

using System.Drawing;

 

namespace Form
{
  public partial class VerifyCode : System.Web.UI.Page
  {
    public static string HZ;
    /// 

    /// 验证码的最大长度
    /// 
    public int MaxLength
    {
      get { return 10; }

    }
    /// 

    /// 验证码的最小长度
    /// 
    public int MinLength
    {
      get { return 1; }
    }
 
    protected void Page_Load(object sender, EventArgs e)
    {
      string[] str = CreateValidateNumber(4);
      string strcode = string.Empty;
      for (int i = 0; i < str.Length; i++)
      {
      strcode += str[i];

      }
    CreateCheckCodeImage(str);
      HZ = strcode;
      Response.Write(HZ);
     //验证码存入session
      Session["ValidateCode"] = HZ;
    }

    /// 

    /// 生成验证码
    /// 
    /// 指定验证码的长度
    /// 验证码
    public string[] CreateValidateNumber(int length)

    {
      string Vchar = "1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,p" +

      ",q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,P,Q" +
      ",R,S,T,U,V,W,X,Y,Z";

      string[] VcArray = Vchar.Split(new Char[] { ',' });//拆分成数组
       string[] num = new string[length];

      int temp = -1;//记录上次随机数值，尽量避避免生产几个一样的随机数

     Random rand = new Random();

      //采用一个简单的算法以保证生成随机数的不同

      for (int i = 1; i < length + 1; i++)

      {

        if (temp != -1)

        {

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

        }
        int t = rand.Next(VcArray.Length-1);
        if (temp != -1 && temp == t)
        {
          return CreateValidateNumber(length);

 

        }

        temp = t;
        num[i - 1] = VcArray[t];
        //num.SetValue(VcArray[t]);
        //VNum += VcArray[t];

      }
      return num;
    }

   private void CreateCheckCodeImage(string[] checkCode)
    {
      if (checkCode == null || checkCode.Length <= 0)
        return;
      System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 32.5)), 60);
      System.Drawing.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);

       //定义颜色

        Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };

        //画图片的背景噪音线
        for (int i = 0; i < 25; i++)

        {
          int cindex = random.Next(7);
          int findex = random.Next(5);
          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(c[cindex]), x1, y1, x2, y2);
        }
        //定义字体
        string[] f = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };

       for (int k = 0; k <= checkCode.Length - 1; k++)
        {
          int cindex = random.Next(7);
          int findex = random.Next(5);
          Font drawFont = new Font(f[findex], 26, (System.Drawing.FontStyle.Bold));
          SolidBrush drawBrush = new SolidBrush(c[cindex]);
          float x = 5.0F;
          float y = 0.0F;
          float width = 42.0F;
          float height = 48.0F;
          int sjx = random.Next(10);
          int sjy = random.Next(image.Height - (int)height);

          RectangleF drawRect = new RectangleF(x + sjx + (k * 25), y + sjy, width, height);
          StringFormat drawFormat = new StringFormat();
          drawFormat.Alignment = StringAlignment.Center;
        g.DrawString(checkCode[k], drawFont, drawBrush, drawRect, drawFormat);
        }
        //画图片的前景噪音点
        for (int i = 0; i < 500; i++)
        {
          int x = random.Next(image.Width);
          int y = random.Next(image.Height); 

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

        }

        int cindex1 = random.Next(7);

        //画图片的边框线

        g.DrawRectangle(new Pen(c[cindex1]), 0, 0, image.Width - 1, image.Height - 1);
       System.IO.MemoryStream ms = new System.IO.MemoryStream();
        image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
        Response.ClearContent();
        Response.ContentType = "image/Gif";
        Response.BinaryWrite(ms.ToArray());

      }

      finally

      {

        g.Dispose();

        image.Dispose();

      }

    }

  }

} 

于是！就可以生成验证码了，然后自己再把编写验证版的判断逻辑写好就可以啦！

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。