1、測試頁面：Default.aspx
<%@ Page Language="C#" AutoEventWireup="true"? CodeFile="Default.aspx.cs" Inherits="_Default" %>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
??? <title>ASP.NET驗證碼</title>
</head>
<body>
??? <form id="form1" runat="server">
??? <div>
??????? 請輸入驗證碼：<input id="txtVI" type="text" name="view_id" runat="server" maxlength="5" size="5"/>
???? <asp:Image id="Image1" runat="server" ImageUrl="ValidateCode.aspx" ImageAlign="Middle" />
??????? <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="您沒有輸入驗證碼" ControlToValidate="txtVI"></asp:RequiredFieldValidator><br />
??????? <asp:Button ID="Button1" runat="server" Text="提 交" OnClick="Button1_Click" /></div>
??? </form>
</body>
</html>
2、測試頁面后臺：Default.aspx.cs
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
?
public partial class _Default : System.Web.UI.Page
{
??? protected void Page_Load(object sender, EventArgs e)
??? {
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??? }
??? protected void Button1_Click(object sender, EventArgs e)
??? {
??????? string VNum;
??????? VNum = Session["VNum"].ToString();
??????? Session.Abandon();
??????? ViewState["VNum"] = VNum;
??????? if (txtVI.Value == ViewState["VNum"].ToString())
??????? {
??????????? Response.Write("<script>alert('驗證碼輸入正確！');</script>");
??????????? return;
??????? }
??????? else
??????? {
??????????? // VIWShow.Text="所填寫的驗證碼不正確！";
??????????? Response.Write("<script>alert('驗證碼輸入錯誤！');</script>");
??????????? return;
??????? }
??? }
}
3、生成驗證碼頁面:ValidateCode.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ValidateCode.aspx.cs" Inherits="ValidateCode" %>
4、生成驗證碼頁面后臺：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing;
?
/* Copyright all(c) 2005 ZhongFeng, http://blog.csdn.net/SW515 */
public partial class ValidateCode : System.Web.UI.Page
{
??? private void Page_Load(object sender, System.EventArgs e)
??? {
??????? this.CreateCheckCodeImage(GenerateCheckCode());
??? }
?
??? #region Web 窗體設計器生成的代碼
??? override protected void OnInit(EventArgs e)
??? {
??????? //
??????? // CODEGEN: 該調用是 ASP.NET Web 窗體設計器所必需的。
??????? //
??????? InitializeComponent();
??????? base.OnInit(e);
??? }
?
??? /// <summary>
??? /// 設計器支持所需的方法 - 不要使用代碼編輯器修改
??? /// 此方法的內容。
??? /// </summary>
??? private void InitializeComponent()
??? {
??????? this.Load += new System.EventHandler(this.Page_Load);
??? }
??? #endregion
?
??? private string GenerateCheckCode()
??? {
??????? int number;
??????? char code;
??????? string checkCode = String.Empty;
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??????? System.Random random = new Random();
?
??????? for (int i = 0; i < 5; i++)
??????? {
??????????? number = random.Next();
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??????????? if (number % 2 == 0)
??????????????? code = (char)('0' + (char)(number % 10));
??????????? else
??????????????? code = (char)('A' + (char)(number % 26));
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??????????? checkCode += code.ToString();
??????? }
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??????? Session["VNum"] = checkCode;
?
??????? return checkCode;
??? }
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??? private void CreateCheckCodeImage(string checkCode)
??? {
??????? if (checkCode == null || checkCode.Trim() == String.Empty)
??????????? return;
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??????? System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
??????? System.Drawing.Graphics g = Graphics.FromImage(image);
?
??????? try
??????? {
??????????? //生成隨機生成器
??????????? Random random = new Random();
?
??????????? //清空圖片背景色
??????????? g.Clear(Color.White);
?
??????????? //畫圖片的背景噪音線
??????????? 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.Silver), x1, y1, x2, y2);
??????????? }
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??????????? 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(checkCode, font, brush, 2, 2);
?
??????????? //畫圖片的前景噪音點
??????????? 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()));
??????????? }
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??????????? //畫圖片的邊框線
??????????? g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
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??????????? 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();
??????? }
??? }
}
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