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  • ASP.Net MVC 生成安全验证码

    ---------html      

    <td>验证码:</td>

               <td>
                   <img src="/Login/CheckCode?ID=1" id="imgCode" alt="单击可刷新" onclick="ClickRemoveChangeCode()"  />
                   <div style="float:right; margin-top: 5px;">
                       <a href="javascript:void(0)" onclick="ClickRemoveChangeCode();return false;">看不清,换一张</a>
                   </div>
               </td>

    -----------jquery

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    //单击重新改变验证码
    function ClickRemoveChangeCode() {
        var code = $("#imgCode").attr("src");
        $("#imgCode").attr("src", code + "1");
    }   

    ------------asp.net mvc 返回文件地址    

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    /// <summary>
    /// 验证码的校验
    /// </summary>
    /// <param name="context"></param>
    /// <returns></returns>
    public ActionResult CheckCode()
    {
        //生成验证码
        ValidateCode validateCode = new ValidateCode();
        string code = validateCode.CreateValidateCode(4);
        Session["ValidateCode"] = code;
        byte[] bytes = validateCode.CreateValidateGraphic(code);
        return File(bytes, @"image/jpeg");
    }
     

    /// <summary>
    /// 验证验证码是否正确
    /// </summary>
    /// <param name="num"></param>
    /// <returns></returns>
    public bool CheckValidateCode(string num) {

    string cnum = Session["ValidateCode"] == null ? "": Session["ValidateCode"].ToString();

    if (num== cnum && !string.IsNullOrEmpty(num))
    {
         return true;
    }
     else
    {
        return false;
    }
    }

    ----生成验证码和绘制背景的类

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    public class ValidateCode
        {
            public ValidateCode()
            {
            }
            /// <summary>
            /// 验证码的最大长度
            /// </summary>
            public int MaxLength
            {
                get return 10; }
            }
            /// <summary>
            /// 验证码的最小长度
            /// </summary>
            public int MinLength
            {
                get return 1; }
            }
            /// <summary>
            /// 生成验证码
            /// </summary>
            /// <param name="length">指定验证码的长度</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;
                }
                //生成随机数字
                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);
                }
                //抽取随机数字
                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));
                }
                //生成验证码
                for (int i = 0; i < length; i++)
                {
                    validateNumberStr += validateNums[i].ToString();
                }
                return validateNumberStr;
            }
     
            //C# MVC 升级版
            /// <summary>
            /// 创建验证码的图片
            /// </summary>
            /// <param name="containsPage">要输出到的page对象</param>
            /// <param name="validateNum">验证码</param>
            public byte[] CreateValidateGraphic(string validateCode)
            {
                Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 22);
                Graphics g = Graphics.FromImage(image);
                try
                {
                    //生成随机生成器
                    Random random = new Random();
                    //清空图片背景色
                    g.Clear(Color.White);
                    //画图片的干扰线
                    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);
                    //画图片的前景干扰点
                    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()));
                    }
                    //画图片的边框线
                    g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                    //保存图片数据
                    MemoryStream stream = new MemoryStream();
                    image.Save(stream, ImageFormat.Jpeg);
                    //输出图片流
                    return stream.ToArray();
                }
                finally
                {
                    g.Dispose();
                    image.Dispose();
                }
            }
     
            /// <summary>
            /// 得到验证码图片的长度
            /// </summary>
            /// <param name="validateNumLength">验证码的长度</param>
            /// <returns></returns>
            public static int GetImageWidth(int validateNumLength)
            {
                return (int)(validateNumLength * 12.0);
            }
            /// <summary>
            /// 得到验证码的高度
            /// </summary>
            /// <returns></returns>
            public static double GetImageHeight()
            {
                return 22.5;
            }
     
        }
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  • 原文地址:https://www.cnblogs.com/lijiasnong/p/5680649.html
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