BS—驗證碼的生成與切換進（程式碼）
阿新 • • 發佈：2019-01-10
一個靜態的登陸的Html頁面（Login.html）
<!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title></title> <script type="text/javascript"> window.onload = function () { var imagecode = document.getElementById("validatecode"); imagecode.onclick= function () { document.getElementById("imgcode").src = "CheckImageCode.ashx?id=" + new Date().getMilliseconds(); } } </script> </head> <body> <form action="Login.ashx" method="post"> 使用者名稱：<input type="text" name="txtName" /><br /> 密碼：<input type="password" name="txtPwd" /><br /> 驗證碼：<input type="text" name="txtcode" /><img src="CheckImageCode.ashx" id="imgcode"/> <a href="javascript:void(0)" id="validatecode">看不清，換一張</a><br /> <input type="submit" value="登陸" /><br /> </form> </body> </html>
一個一般處理程式：（CheckImageCode.ashx）
using System; using System.Collections.Generic; using System.Linq; using System.Web; using Common; namespace 驗證碼學習 { /// <summary> /// CheckImageCode 的摘要說明 /// </summary> public class CheckImageCode : IHttpHandler { public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/plain"; ValidateCode validatecode = new ValidateCode(); string code = validatecode.CreateValidateCode(4); validatecode.CreateValidateGraphic(code, context); } public bool IsReusable { get { return false; } } } }
一個封裝好的驗證碼替換類
using System; using System.Collections.Generic; using System.Drawing; using System.Drawing.Drawing2D; using System.Drawing.Imaging; using System.IO; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Web; namespace Common { public class ValidateCode { public ValidateCode() { } /// <summary> /// 驗證碼的最大長度 /// </summary> public int MaxLength { get { return 10; } } /// <summary> /// 驗證碼的最小長度 /// </summary> public int MinLength { get { return 1; } } /// <summary> /// 生成驗證碼 /// </summary> /// <param name="length">指定驗證碼的長度</param> /// <returns></returns> public string CreateValidateCode(int length) { int[] randMembers = new int[length]; int[] validateNums = new int[length]; string validateNumberStr = ""; //生成起始序列值 int seekSeek = unchecked((int)DateTime.Now.Ticks); Random seekRand = new Random(seekSeek); int beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000); int[] seeks = new int[length]; for (int i = 0; i < length; i++) { beginSeek += 10000; seeks[i] = beginSeek; } //生成隨機數字 for (int i = 0; i < length; i++) { Random rand = new Random(seeks[i]); int pownum = 1 * (int)Math.Pow(10, length); randMembers[i] = rand.Next(pownum, Int32.MaxValue); } //抽取隨機數字 for (int i = 0; i < length; i++) { string numStr = randMembers[i].ToString(); int numLength = numStr.Length; Random rand = new Random(); int numPosition = rand.Next(0, numLength - 1); validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1)); } //生成驗證碼 for (int i = 0; i < length; i++) { validateNumberStr += validateNums[i].ToString(); } return validateNumberStr; } /// <summary> /// 建立驗證碼的圖片 /// </summary> /// <param name="containsPage">要輸出到的page物件</param> /// <param name="validateNum">驗證碼</param> public void CreateValidateGraphic(string validateCode, HttpContext context) { Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 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); //畫圖片的干擾線 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 Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic)); //漸變. LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true); g.DrawString(validateCode, font, brush, 3, 2); //畫圖片的前景干擾點 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); //儲存圖片資料 MemoryStream stream = new MemoryStream(); image.Save(stream, ImageFormat.Jpeg); //輸出圖片流 context.Response.Clear(); context.Response.ContentType = "image/jpeg"; context.Response.BinaryWrite(stream.ToArray()); } finally { g.Dispose(); image.Dispose(); } } /// <summary> /// 得到驗證碼圖片的長度 /// </summary> /// <param name="validateNumLength">驗證碼的長度</param> /// <returns></returns> public static int GetImageWidth(int validateNumLength) { return (int)(validateNumLength * 12.0); } /// <summary> /// 得到驗證碼的高度 /// </summary> /// <returns></returns> public static double GetImageHeight() { return 22.5; } } }