asp.net 圖片驗證碼的HtmlHelper

一個圖片驗證碼的HtmlHelper，原來的調用代碼如下：

<img id="validateCode" mailto:src='@Url.Action(%22GetValidateCode%22)'/> <script language="javascript" type="text/javascript"> $(document).ready(function () { $("#validateCode").bind("click", function () { var url = $(this).attr("src"); url += "?" + Math.random(); $(this).attr("src", url); }); }); </script>

封裝成HtmlHelper後：
@Html.ValidateCode()
使用步驟如下：
1.建一個驗證碼Helper

using System; using System.Collections.Generic; using System.ComponentModel; using System; using System.Collections.Generic; using System.Diagnostics.CodeAnalysis; using System.Globalization; using System.Linq.Expressions; using System.Security.Policy; using System.Text; using System.Web; using System.Web.Mvc; using System.Web.Mvc.Resources; using System.Web.Routing; namespace MvcApplication1 { public static class ValidateCodeHelper { private const string IdPrefix = "validateCode"; private const int Length = 4; public static MvcHtmlString ValidateCode(this HtmlHelper helper) { return ValidateCode(helper, IdPrefix); } public static MvcHtmlString ValidateCode(this HtmlHelper helper,string id) { return ValidateCode(helper, id, Length); } public static MvcHtmlString ValidateCode(this HtmlHelper helper, string id, int length) { return ValidateCode(helper, id, length, null); } public static MvcHtmlString ValidateCode(this HtmlHelper helper, string id, object htmlAttributes) { return ValidateCode(helper, id, Length, htmlAttributes); } public static MvcHtmlString ValidateCode(this HtmlHelper helper, int length, object htmlAttributes) { return ValidateCode(helper, IdPrefix, length, htmlAttributes); } public static MvcHtmlString ValidateCode(this HtmlHelper helper, object htmlAttributes) { return ValidateCode(helper, 4, htmlAttributes); } public static MvcHtmlString ValidateCode(this HtmlHelper helper, int length) { return ValidateCode(helper,length, null); } public static MvcHtmlString ValidateCode(this HtmlHelper helper,string id,int length,object htmlAttributes) { string finalId = id + "_imgValidateCode"; var tagBuild = new TagBuilder("img"); tagBuild.GenerateId(finalId); var defaultController = ((Route)RouteTable.Routes["Default"]).Defaults["controller"] + "/"; var controller = HttpContext.Current.Request.Url.Segments.Length == 1 ? defaultController : HttpContext.Current.Request.Url.Segments[1]; tagBuild.MergeAttribute("src", string.Format("/{0}GetValidateCode?length={1}",controller,length)); tagBuild.MergeAttribute("alt", "看不清？點我試試看！"); tagBuild.MergeAttribute("style","cursor:pointer;"); tagBuild.MergeAttributes(AnonymousObjectToHtmlAttributes(htmlAttributes)); var sb = new StringBuilder(); sb.Append("<script language=\"javascript\" type=\"text/javascript\">"); sb.Append("$(document).ready(function () {"); sb.AppendFormat("$(\"#{0}\").bind(\"click\", function () {{", finalId); //sb.Append("$(this).attr(\"style\", \"cursor:pointer;\");"); sb.Append("var url = $(this).attr(\"src\");"); sb.Append("url += \"&\" + Math.random();"); sb.Append("$(this).attr(\"src\", url);"); sb.Append("});"); sb.Append("});"); sb.Append("</script>"); return MvcHtmlString.Create(tagBuild+sb.ToString()); } public static RouteValueDictionary AnonymousObjectToHtmlAttributes(object htmlAttributes) { var result = new RouteValueDictionary(); if (htmlAttributes != null) { foreach (PropertyDescriptor property in TypeDescriptor.GetProperties(htmlAttributes)) { result.Add(property.Name.Replace('_', '-'), property.GetValue(htmlAttributes)); } } return result; } } }

2.產生驗證碼的代碼：

using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Drawing; using System.Drawing.Drawing2D; using System.IO; using System.Drawing.Imaging; namespace MvcApplication1 { 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> /// 產生驗證碼 /// </summary> /// <param name="length">指定驗證碼的長度</param> /// <returns></returns> public string CreateValidateCode(int length) { var randMembers = new int[length]; var validateNums = new int[length]; var validateNumberStr = ""; //產生起始序列值 var seekSeek = unchecked((int)DateTime.Now.Ticks); var seekRand = new Random(seekSeek); var beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000); var seeks = new int[length]; for (var i = 0; i < length; i++) { beginSeek += 10000; seeks[i] = beginSeek; } //產生隨機數字 for (var i = 0; i < length; i++) { var rand = new Random(seeks[i]); var pownum = 1 * (int)Math.Pow(10, length); randMembers[i] = rand.Next(pownum, Int32.MaxValue); } //抽取隨機數字 for (var i = 0; i < length; i++) { var numStr = randMembers[i].ToString(); var numLength = numStr.Length; var rand = new Random(); var numPosition = rand.Next(0, numLength - 1); validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1)); } //產生驗證碼 for (var i = 0; i < length; i++) { validateNumberStr += validateNums[i].ToString(); } return validateNumberStr; } /// <summary> /// 建立驗證碼的圖片 /// </summary> /// <param name="validateCode">驗證碼</param> public byte[] CreateValidateGraphic(string validateCode) { var image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 22); var g = Graphics.FromImage(image); try { //產生隨機產生器 var random = new Random(); //清空圖片背景色 g.Clear(Color.White); //畫圖片的幹擾線 for (int i = 0; i < 25; i++) { var x1 = random.Next(image.Width); var x2 = random.Next(image.Width); var y1 = random.Next(image.Height); var 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)); string[] fontName = { "華文新魏", "宋體", "圓體", "黑體", "隸書" }; var font = new Font(fontName[new Random().Next(0, validateCode.Length)], 12, (FontStyle.Bold | FontStyle.Italic)); var 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); //畫圖片的前景幹擾點 for (var i = 0; i < 100; i++) { var x = random.Next(image.Width); var 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 var stream = new MemoryStream(); image.Save(stream, ImageFormat.Jpeg); //輸出圖片流 return 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 23; } } }

3.建一個BaseController

using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; namespace MvcApplication1 { public class BaseController:Controller { public ActionResult GetValidateCode(int length) { var vCode = new ValidateCode(); var code = vCode.CreateValidateCode(length); Session["ValidateCode"] = code; var bytes = vCode.CreateValidateGraphic(code); return File(bytes, @"image/gif"); } protected string GetValidateCode() { return Session["ValidateCode"].ToString(); } } }

4.讓Controller繼承BaseController：

using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using System.Web.Security; namespace MvcApplication1.Controllers { public class HomeController :BaseController { public ActionResult Index() { ViewBag.Message = "Welcome to ASP.NET MVC!"; return View(); } public ActionResult About() { var code = GetValidateCode(); return View(); } } }

5.頁面調用代碼：

@using MvcApplication1 @{ ViewBag.Title = "About Us"; } <h2>About</h2> <p> Put content here. </p> @Html.ValidateCode()

6.驗證碼的：