本文執行個體講述了C#驗證碼的建立與使用方法。分享給大家供大家參考，具體如下：
1、C#建立驗證碼
① 建立擷取驗證碼頁面（ValidateCode.aspx）
<html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title>擷取驗證碼</title></head><body> <form id="form1" runat="server"> <p>擷取驗證碼</p> </form></body></html>
② 編寫擷取驗證碼代碼（ValidateCode.aspx.cs）
/// <summary>/// 驗證碼類型(0-字母數字混合,1-數字,2-字母)/// </summary>private string validateCodeType = "0";/// <summary>/// 驗證碼字元個數/// </summary>private int validateCodeCount = 4;/// <summary>/// 驗證碼的字元集，去掉了一些容易混淆的字元/// </summary>char[] character = { '2', '3', '4', '5', '6', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };protected void Page_Load(object sender, EventArgs e){ //取消緩衝 Response.BufferOutput = true; Response.Cache.SetExpires(DateTime.Now.AddMilliseconds(-1)); Response.Cache.SetCacheability(System.Web.HttpCacheability.NoCache); Response.AppendHeader("Pragma", "No-Cache"); //擷取設定參數 if (!string.IsNullOrEmpty(Request.QueryString["validateCodeType"])) { validateCodeType = Request.QueryString["validateCodeType"]; } if (!string.IsNullOrEmpty(Request.QueryString["validateCodeCount"])) { int.TryParse(Request.QueryString["validateCodeCount"], out validateCodeCount); } //產生驗證碼 this.CreateCheckCodeImage(GenerateCheckCode());}private string GenerateCheckCode(){ char code ; string checkCode = String.Empty; System.Random random = new Random(); for (int i = 0; i < validateCodeCount; i++) { code = character[random.Next(character.Length)]; // 要求全為數字或字母 if (validateCodeType == "1") { if ((int)code < 48 || (int)code > 57) { i--; continue; } } else if (validateCodeType == "2") { if ((int)code < 65 || (int)code > 90) { i--; continue; } } checkCode += code; } Response.Cookies.Add(new System.Web.HttpCookie("CheckCode", checkCode)); this.Session["CheckCode"] = checkCode; return checkCode;}private void CreateCheckCodeImage(string checkCode){ if (checkCode == null || checkCode.Trim() == String.Empty) return; System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length*15.0+40)), 23); System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image); try { //產生隨機產生器 Random random = new Random(); //清空圖片背景色 g.Clear(System.Drawing.Color.White); //畫圖片的背景雜音線 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 System.Drawing.Pen(System.Drawing.Color.Silver), x1, y1, x2, y2); } System.Drawing.Font font = new System.Drawing.Font("Arial", 14, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic)); System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new System.Drawing.Rectangle(0, 0, image.Width, image.Height), System.Drawing.Color.Blue, System.Drawing.Color.DarkRed, 1.2f, true); int cySpace = 16; for (int i = 0; i < validateCodeCount; i++) { g.DrawString(checkCode.Substring(i, 1), font, brush, (i + 1) * cySpace, 1); } //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, System.Drawing.Color.FromArgb(random.Next())); } //畫圖片的邊框線 g.DrawRectangle(new System.Drawing.Pen(System.Drawing.Color.Silver), 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(); }}
2、驗證碼的使用
① 驗證碼的前段顯示代碼
代碼如下:
<img src="/ValidateCode.aspx?ValidateCodeType=1&0.011150883024061309" onclick="this.src='/ValidateCode.aspx?ValidateCodeType=1&'+Math.random();" id="imgValidateCode" alt="點擊重新整理驗證碼" title="點擊重新整理驗證碼" style="cursor: pointer;">
② 建立驗證碼測試頁面（ValidateTest.aspx）
<html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title>驗證碼測試</title></head><body> <form id="form1" runat="server"> <p> <input runat="server" id="txtValidate" /> <img src="/ValidateCode.aspx?ValidateCodeType=1&0.011150883024061309" onclick="this.src='/ValidateCode.aspx?ValidateCodeType=1&'+Math.random();" id="imgValidateCode" alt="點擊重新整理驗證碼" title="點擊重新整理驗證碼" style="cursor: pointer;"> <asp:Button runat="server" id="btnVal" Text="提交" onclick="btnVal_Click" /> </p> </form></body></html>
③ 編寫驗證碼測試的提交代碼（ValidateTest.aspx.cs）
protected void btnVal_Click(object sender, EventArgs e){ bool result = false; //驗證結果 string userCode = this.txtValidate.Value; //擷取使用者輸入的驗證碼 if (String.IsNullOrEmpty(userCode)) { //請輸入驗證碼 return; } string validCode = this.Session["CheckCode"] as String; //擷取系統產生的驗證碼 if (!string.IsNullOrEmpty(validCode)) { if (userCode.ToLower() == validCode.ToLower()) { //驗證成功 result = true; } else { //驗證失敗 result = false; } }}Start building with 50+ products and up to 12 months usage for Elastic Compute Service
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