愛上MVC3系列~無刷新驗證碼

回到目錄

在MVC中進行留言，評論等功能時，不可避免會用到表單提交時的驗證碼問題，有時，我們的作法是，當表單被提交后，在controller里去判斷驗證碼的正確與否，但我認為這種用戶體驗是很差的，今天正好有后時間，把這方法的東西總結一下：

首先，在公用項目中建立一個生成圖片驗證碼的類型ValidateCode，代碼如下：

  /// <summary>
  /// 生成驗證碼對象
  /// </summary>
  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="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 * 14.0), 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", 14, (FontStyle.Bold | FontStyle.Italic));
        LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
        Color.Blue, Color.DarkRed, 1.5f, 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();
      }
    }
  }

然后，在當前公用的controller中添加一個返回文件類型的action,當然也可以是所有返回類型的基類ActionResult，這個方法用來返回一個圖像對象

    /// <summary>
    /// 生成驗證碼圖像對象
    /// </summary>
    /// <returns></returns>
    public ActionResult GetValidateCode()
    {
      ValidateCode vCode = new ValidateCode();
      string code = vCode.CreateValidateCode(4);
      Session["ValidateCode"] = code;
      byte[] bytes = vCode.CreateValidateGraphic(code);
      return File(bytes, @"image/jpeg");
    }

再次，需要我們寫一個返回當前驗證嗎的方法，這是作無刷新驗證碼的關鍵

    /// <summary>
    /// 得到當前驗證碼
    /// </summary>
    /// <returns></returns>
    public ActionResult GetCurrentValidateCode()
    {
      return Content(Session["ValidateCode"].ToString());
    }

最后，就是頁面上的事了，看代碼：

             <div id="ValidateCodeSpan">
                    請輸入驗證碼：@Html.TextBox("VCode")
                    <img id="valiCode" style="cursor: pointer;" src="/Common/GetValidateCode" alt="看不清？請點我" />
                    @Html.Hidden("ValidateCode")
                    <script type="text/javascript">
                        $(function () {
                            //首次加載
                            $("#valiCode").attr("src","/Common/GetValidateCode?time=" + (new Date()).getTime());
                            $.get("/Common/GetCurrentValidateCode", function (data) {
                                $("#ValidateCode").val(data);
                            });
                            //單擊驗證碼事件
                            $("#valiCode").bind("click", function () {
                                this.src = "/Common/GetValidateCode?time=" + (new Date()).getTime();
                                $.get("/Common/GetCurrentValidateCode", function (data) {
                                    $("#ValidateCode").val(data);
                                });
                            });
                        });
                    </script>
                </div>

 

 回到目錄