ASP.NET 实现验证码以及刷新验证码

实现代码

 /// <summary>
     /// 生成验证码图片，保存session名称VerificationCode
     /// </summary>
     public static void CreateVerificationCode()
     {
         int number;
         string checkCode = string.Empty;

         //随机数种子
         Random randoms = new Random();

         for (int i = ; i < ; i++) //校验码长度为4
         {
             //随机的整数
             number = randoms.Next();

             //字符从0-9,A-Z中随机产生,对应的ASCII码分别为
             //48-57,65-90
             number = number % ;
             if (number < )
             {
                 number += ;
             }
             else
             {
                 number += ;
             }
             checkCode += ((char)number).ToString();
         }

         //在session中保存校验码
         System.Web.HttpContext.Current.Session["VerificationCode"] = checkCode;

         //若校验码为空，则直接返回
         if (checkCode == null || checkCode.Trim() == String.Empty)
         {
             return;
         }
         //根据校验码的长度确定输出图片的长度
         System.Drawing.Bitmap image = new System.Drawing.Bitmap(, );//(int)Math.Ceiling(Convert.ToDouble(checkCode.Length * 15))
         //创建Graphics对象
         Graphics g = Graphics.FromImage(image);
         try
         {
             //生成随机数种子
             Random random = new Random();
             //清空图片背景色
             g.Clear(Color.White);
             //画图片的背景噪音线 10条
             //---------------------------------------------------
             for (int i = ; i < ; i++)
             {
                 //噪音线起点坐标(x1,y1),终点坐标(x2,y2)
                 int x1 = random.Next(image.Width);
                 int x2 = random.Next(image.Width);
                 int y1 = random.Next(image.Height);
                 int y2 = random.Next(image.Height);

                 //用银色画出噪音线
                 g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
             }
             //---------------------------------------------------
             //Brush b = Brushes.Silver;
             //g.FillRectangle(b, 0, 0, image.Width, image.Height);
             //---------------------以上两种任选其一------------------------------
             //输出图片中校验码的字体: 12号Arial,粗斜体
             Font font = new Font("Arial", , (FontStyle.Bold | FontStyle.Italic));

             //线性渐变画刷
             LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(, , image.Width, image.Height), Color.Blue, Color.Purple, 1.2f, true);
             g.DrawString(checkCode, font, brush, , );

             //画图片的前景噪音点 50个
             for (int i = ; i < ; 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.Peru), , , image.Width - , image.Height - );

             //创建内存流用于输出图片
             using (MemoryStream ms = new MemoryStream())
             {
                 //图片格式指定为png
                 image.Save(ms, ImageFormat.Jpeg);
                 //清除缓冲区流中的所有输出
                 System.Web.HttpContext.Current.Response.ClearContent();
                 //输出流的HTTP MIME类型设置为"image/Png"
                 System.Web.HttpContext.Current.Response.ContentType = "image/Jpeg";
                 //输出图片的二进制流
                 System.Web.HttpContext.Current.Response.BinaryWrite(ms.ToArray());
             }
         }
         finally
         {
             //释放Bitmap对象和Graphics对象
             g.Dispose();
             image.Dispose();
         }
     }

Create Verification Code

创建一个aspx页面

 <%@ Page Language="C#" AutoEventWireup="true" CodeFile="AuthCode.aspx.cs" Inherits="AuthCode" %>

 <%Help.CreateVerificationCode(); %>

Create WebFrom

添加HTML代码,引用

 <div class="positionR">
     <label>验证码：</label>
     <span class="style1"> *</span>
     <input type="text" class="yanZm" runat="Server" reg="^.+$" id="txtAuthCode" tip="请输入验证码!" />
     <img class="yanZm_img" src="AuthCode.aspx" alt="" id="imgAuthCode" />
 </div>

HTML Code

如何实现刷新?

     <script type="text/javascript">
         $("#imgAuthCode").click(function () {
             $(this).attr("src", "AuthCode.aspx?code=" + (new Date()).getTime());
         });
     </script>

Refresh - JS Code

效果图

 注明:内容来源不可考 = = 验证码图片生成非原创,如果谁知道原作者请告诉我.

DEMO