asp.net实现登录页验证码功能

一、效果

二、实现代码:

项目资源分布

主页Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>





        

    


    

    

    

         

                

                    
                
                

                           
                    
                    换一张
                    
                    
                
            
          
    
    

Default.aspx.cs 

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)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        string code = tbx_yzm.Text;
        HttpCookie htco = Request.Cookies["ImageV"];
        string scode = htco.Value.ToString();
        if (code.ToUpper() != scode)
        {
            Response.Write("");
        }
        else
        {
            this.tbx_yzm.Text = "";
            Response.Write("");
        }
    }
}

ImageCode.aspx(啥也不用动)

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ImageCode.aspx.cs" Inherits="ImageCode" %>






    


    

    

    
    
    

ImageCode.aspx.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class ImageCode : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string tmp = RndNum(4);
        HttpCookie a = new HttpCookie("ImageV ", tmp);
        Response.Cookies.Add(a);
        this.ValidateCode(tmp);
    }
    private void ValidateCode(string VNum)
    {

        Bitmap Img = null;

        Graphics g = null;

        MemoryStream ms = null;

        int gheight = VNum.Length * 12;

        Img = new Bitmap(gheight, 25);

        g = Graphics.FromImage(Img);

        //生成随机生成器

        Random random = new Random();

        //背景颜色
        g.Clear(Color.White);

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

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

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

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

        }


        //文字字体
        Font f = new Font("Arial Black ", 12);

        //文字颜色
        SolidBrush s = new SolidBrush(Color.Blue);

        g.DrawString(VNum, f, s, 3, 3);

        ms = new MemoryStream();

        Img.Save(ms, ImageFormat.Jpeg);

        Response.ClearContent();

        Response.ContentType = "image/Jpeg ";

        Response.BinaryWrite(ms.ToArray());

        g.Dispose();
        Img.Dispose();
        Response.End();

    }
    private string RndNum(int VcodeNum)
    {

        string Vchar = "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";

        string[] VcArray = Vchar.Split(new Char[] { ',' });

        string VNum = " ";
        int temp = -1;
        Random rand = new Random();

        for (int i = 1; i < VcodeNum + 1; i++)
        {
            if (temp != -1)
            {
                rand = new Random(i * temp * unchecked((int)DateTime.Now.Ticks));

            }
            int t = rand.Next(35);
            if (temp != -1 && temp == t)
            {
                return RndNum(VcodeNum);

            }
            temp = t;
            VNum += VcArray[t];

        }

        return VNum;

    }
}

三、资源下载(如果您还是不会的话，可以下载资源)

链接：https://pan.baidu.com/s/1kbq3Z0gaJPXa9GAI-Y6aPg 
提取码：snp1