纯手写验证码ＭＶＣ中

生成验证码： 
 public void Validate()
        {
            Random r = new Random();
            string str = null;
            for (int i = 0; i < 5; i++)
            {
                int rNumber = r.Next(0, 10);
                str += rNumber;               //随机取0到10之间的5个随机数存入字符串变量str
            }
            this.Session["Validate"] = str;  //将str写入session
            Bitmap bmp = new Bitmap(100, 30); //新建一块画布，大小为 宽100 高30
            Graphics g = Graphics.FromImage(bmp);  //创建一个Graphics 画笔，操作bmp
            g.Clear(System.Drawing.Color.White);    //画布的初始颜色设为白色，初始颜色为黑色；
            for (int i = 0; i < 5; i++)
            {
                Point p = new Point(i * 20, 0);
                string[] fonts = { "微软雅黑", "宋体", "黑体", "隶书", "仿宋" };
                Color[] colors = { Color.Maroon, Color.Blue, Color.Black, Color.Red, Color.Green };
                g.DrawString(str[i].ToString(), new Font(fonts[r.Next(0, 5)], 20, FontStyle.Bold), new SolidBrush(colors[r.Next(0, 5)]), p);   //以此将5个数字写在画布上
                //g.DrawImage(bmp, 1, 1);
            }
            for (int i = 0; i < 15; i++)
            {
                Point p1 = new Point(r.Next(0, bmp.Width), r.Next(0, bmp.Height));
                Point p2 = new Point(r.Next(0, bmp.Width), r.Next(0, bmp.Height)); //画线
                g.DrawLine(new Pen(Brushes.Green), p1, p2);

            }
            for (int i = 0; i < 500; i++)
            {
                Point p = new Point(r.Next(0, bmp.Width), r.Next(0, bmp.Height));//画点点
                bmp.SetPixel(p.X, p.Y, Color.Black);
            }

            MemoryStream stream = new MemoryStream();
            //保存图片
            bmp.Save(stream, ImageFormat.Gif);   //保存为.gif数据
            base.Response.ClearContent();
            base.Response.ContentType = "image/Gif";
            base.Response.BinaryWrite(stream.ToArray());
        }

获取验证码：　　 

string Validate = this.Session["Validate"].ToString();   //获取写在session内的验证码
            string Validate2 = Request["Validate"];
            if (Validate == Validate2)     //如果 验证码通过，
            {
               　．．．
            }

前台：
   @using (Html.BeginForm())
                {  　
                    <p class="row-fluid">
                        @Html.Label("验证码：", new { @class = "span4 magino" })
                        @Html.TextBox("Validate")
                        <img src="/Home/Validate" onclick="this.src = ‘/Home/Validate?‘ + Math.random();" id="imgValidateCode" alt="点击刷新验证码" title="点击刷新验证码" style="cursor: pointer;" class="span3">
                        
                    </p>
                }