1. 新建一個Validate.aspx，然后在Validate.aspx.cs編寫代碼：
using System;using System.Collections;using System.ComponentModel;using System.Data;using System.Web;using System.Drawing;using System.Web.sessionState;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.HtmlControls;using System.Drawing.Imaging;using System.IO;
public partial class Validate : System.Web.UI.Page{ PRotected void Page_Load(object sender, EventArgs e) { this.CreateCheckCodeImage(RndNum());
} private string RndNum() { int number; char code; string checkCode = String.Empty;
System.Random random = new Random();
for (int i = 0; i < 4; i++) { number = random.Next(); if (number % 2 == 0) code = (char)('0' + (char)(number % 10)); else code = (char)('A' + (char)(number % 26)); checkCode += code.ToString(); }
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 * 12.5)), 22); 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); }
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())); } //畫圖片的邊框線 g.DrawRectangle(new Pen(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. 在前臺你想添加的頁面添加這段代碼：（我這里假設是在登錄頁面Login.aspx中添加圖片驗證碼）
<img id="ImageCode" src="../Validate.aspx" style="cursor:pointer" onmouseup="RefreshImage()" alt="點擊重刷新"/>還需要在<head>...</head>之間添加這段代碼：
<script language ="javascript" type="text/Javascript" > function RefreshImage()
{ var img = document.getElementById("ImageCode"); // 這里的ImageCode就是上面你取圖片的Id名字，這里要一致！ img.src = img.src + '?'; } </script>
3. 在后臺Login.aspx.cs中添加實現代碼：
引用......
public partial class Login : System.Web.UI.Page{ protected void Page_Load(object sender, EventArgs e) {
}
// 登錄按鈕點擊事件處理 protected void btnLogin_Click(object sender, ImageClickEventArgs e) { User user = new User(); user.LoginId = this.txt_LoginId.Text.Trim(); user.LoginPwd = this.txt_LoginPwd.Text.Trim(); if (this.txtCode.Text.ToLower() == Session["CheckCode"].ToString().ToLower()) { Response.Redirect("Index.aspx");
else { Session["user"] = null; this.Page.ClientScript.RegisterStartupScript(this.GetType(), "str", "<script>alert(/"登錄失?。。?")</script>"); } } else { this.Page.ClientScript.RegisterStartupScript(this.GetType(), "str", "<script>alert(/"驗證碼錯誤?。?")</script>"); }
}
// 新用戶注冊按鈕點擊事件處理 protected void btn_Register_Click(object sender, ImageClickEventArgs e) { Response.Redirect("Register.aspx"); }}
最后運行出來的驗證碼就是這個樣子的~~
當然如果你想實現在其他頁面上代碼會有些小的變動，但是基本代碼就這些~~
Thanks~~
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