webform 图片验证码制作

时间：2022-08-27 15:13:31
 界面：
1 <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default2.aspx.cs" Inherits="Default2" %>

 <!DOCTYPE html>

 <html xmlns="http://www.w3.org/1999/xhtml">

 <head runat="server">

     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

     <title></title>

 </head>

 <body>

     <form id="form1" runat="server">

         <div>

             <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

             <asp:Image ID="Image1" runat="server" ImageUrl="YZM.aspx" />

             <asp:Button ID="Button1" runat="server" Text="验证" />

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

         </div>

     </form>

 </body>

 </html>

 <script type="text/javascript">

     var a = ;

     //点击图片更换验证码

     document.getElementById("Image1").onclick = function () {

         this.setAttribute("src", "yzm.aspx?id=" + a);

         a++;

     }

 </script>

后台：

 using System;

 using System.Collections.Generic;

 using System.Linq;

 using System.Web;

 using System.Web.UI;

 using System.Web.UI.WebControls;

 public partial class Default2 : System.Web.UI.Page

 {

     protected void Page_Load(object sender, EventArgs e)

     {

         Button1.Click += Button1_Click;

     }

     void Button1_Click(object sender, EventArgs e)

     {

         string t1 = TextBox1.Text;

         string t2 = Session["YZM"].ToString();

         if (t1.ToUpper() == t2.ToUpper())

         {

             Label1.Text = "验证成功！";

         }

         else

         {

             Label1.Text = "验证失败！";

         }

     }

 }

验证码制作：

 using System;

 using System.Collections.Generic;

 using System.Linq;

 using System.Web;

 using System.Web.UI;

 using System.Web.UI.WebControls;

 using System.Drawing;

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

 {

     protected void Page_Load(object sender, EventArgs e)

     {

         Bitmap img = new Bitmap(, );//验证码图片大小

         Graphics g = Graphics.FromImage(img);

         Random r = new Random();

         //背景色

         List<Color> clist = new List<Color>();

         clist.Add(Color.Yellow);

         clist.Add(Color.Green);

         clist.Add(Color.Blue);

         clist.Add(Color.Pink);

         clist.Add(Color.Orange);

         clist.Add(Color.AliceBlue);

         clist.Add(Color.Aqua);

         clist.Add(Color.Cyan);

         clist.Add(Color.DarkOliveGreen);

         clist.Add(Color.Black);

         g.FillRectangle(new SolidBrush(clist[r.Next(, clist.Count)]), , , , );

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

         {

             Color ccc = clist[r.Next(, clist.Count)];//随机颜色

             Pen ppp = new Pen(new SolidBrush(ccc), r.Next(, ));//随机线条

             g.DrawLine(ppp, new PointF(r.Next(, ), r.Next(, )), new PointF(r.Next(, ), r.Next(, )));

         }

         //验证码

         string all = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

         string s = "";

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

         {

             int a = r.Next(all.Length);//随机取数

             s += all.Substring(a, );

         }

         Session["YZM"] = s;

         g.DrawString(s, new Font("微软雅黑", ), new SolidBrush(Color.Red), new PointF(, ));

         img.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Png);

         Response.End();

     }

 }

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