我們在項目中的NewWeb.Common類庫裡面建立一個類用來存放生成驗證碼的代碼。 這裡我類的名字叫 ValidateCode 生成驗證碼（ValidateCode）類的代碼： 這時需要在程式中引入兩個命名空間 System.Drawing和System.Web。 完成之後到LoginContro ...
我們在項目中的NewWeb.Common類庫裡面建立一個類用來存放生成驗證碼的代碼。
這裡我類的名字叫 ValidateCode
生成驗證碼（ValidateCode）類的代碼：
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 NewWeb.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> /// 創建驗證碼的圖片 /// </summary> /// <param name="context">要輸出到的page對象</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)); 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); //保存圖片數據 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; } //C# MVC 升級版 /// <summary> /// 創建驗證碼的圖片 /// </summary> /// <param name="containsPage">要輸出到的page對象</param> /// <param name="validateNum">驗證碼</param> public byte[] CreateValidateGraphic(string validateCode) { 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)); 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); //保存圖片數據 MemoryStream stream = new MemoryStream(); image.Save(stream, ImageFormat.Jpeg); //輸出圖片流 return stream.ToArray(); } finally { g.Dispose(); image.Dispose(); } } } }
這時需要在程式中引入兩個命名空間 System.Drawing和System.Web。
完成之後到LoginController控制器裡面去新建一個ActionResult 就叫ValidateCode 用於生成驗證碼。（這裡要先對NewWeb.Common引用）
生成驗證碼代碼如下:
public ActionResult ValidateCode() { Common.ValidateCode validateCode = new Common.ValidateCode(); string code = validateCode.CreateValidateCode(4); //生成的驗證碼4個長度 Session["validateCode"] = code; byte[] buffer = validateCode.CreateValidateGraphic(code);//創建驗證碼圖片 return File(buffer, "image/jpeg");//返回圖片 }
到Login視圖裡面的index頁面去把img的src補充為：
<tr>
<td style="width:20px"></td>
<td><img id="image" src="/Login/ValidateCode/?id=1" style="float: left; height: 24px;" /></td>
<td><a href="javascript:void(0)" onclick="changeCheckCode();return false;">看不清，換一張</a></td>
</tr>
就可以看到頁面上面顯示出來驗證碼
下麵要做的就是點擊切換驗證碼，這是通過js實現的代碼
<script type="text/javascript"> $(function () { initWin(); //初始化登錄窗體 changeCheckCode(); //切換驗證碼 }); function initWin() { $("#win").window({ title: "登錄", width: 400, height: 270, collapsible: false, minimizable: false, maximizable: false, closable: false, modal: true, resizable: false, }); } //切換驗證碼 function changeCheckCode() { $("#changeVcode").click(function () { $("#image").attr("src", $("#image").attr("src") + 1); }); } </script>
