页面:

            
      
    
       
        
        
                     
          
                           
 验证码 
                           
 
             
                           
  
                           
 换一张 
                      
                      
                           
 
             
                      
                 
        
    
       
    
      

 后台代码:

/// 
        /// 登录        /// 
        ///         protected void LoginSubmits(object sender, EventArgs e)        {            CheckLogin();        }        #region 私有方法        #region        public static Boolean IsNotNull(Object str)        {            return !IsNull(str);        }        public static Boolean IsNull(Object str)        {            return str == null;        }        public static void Show(System.Web.UI.Page page, string msg)        {            page.ClientScript.RegisterStartupScript(page.GetType(), "message",                "");        }        #endregion        private void CheckLogin()        {            if (tbCheckCode.Text.Trim() == "")            {                Show(this, "验证码不能为空!");                return;            }            else            {                if (IsNotNull(Session["ValidateCheckCode"]))                {                    if (tbCheckCode.Text.Trim() != Session["ValidateCheckCode"].ToString())                    {                        Show(this, "验证码填写不正确!");                        tbCheckCode.Text = "";                        return;                    }                }                else                {                    Show(this, "请刷新验证码！");                    return;                }            }        }        #endregion    }}

 生成验证码:

using System;using System.Drawing;using System.Text;using System.Web;namespace Web.TEXT{    public partial class VerifyCode : System.Web.UI.Page    {        public Encoding GB = Encoding.GetEncoding("GB2312");        protected void Page_Load(object sender, EventArgs e)        {            VerifyCode v = new VerifyCode();            v.Length = this.length;            v.FontSize = this.fontSize;            v.Chaos = this.chaos;            v.BackgroundColor = this.backgroundColor;            v.ChaosColor = this.chaosColor;            v.CodeSerial = this.codeSerial;            v.Colors = this.colors;            v.Fonts = this.fonts;            v.Padding = this.padding;            string code = v.CreateVerifyCode(); //取随机码            v.CreateImageOnPage(code, this.Context); // 输出图片            Response.Cookies.Add(new HttpCookie("CheckCode", code.ToUpper())); // 使用Cookies取验证码的值            System.Web.HttpContext.Current.Session["ValidateCheckCode"] = code;            //return checkCode;        }        #region 验证码长度(默认4个验证码的长度)        private int length = 4;         public int Length        {            get { return length; }            set { length = value; }        }        #endregion        #region 验证码字体大小(为了显示扭曲效果，默认40像素，可以自行修改)        private int fontSize = 12;        public int FontSize        {            get { return fontSize; }            set { fontSize = value; }        }        #endregion        #region 边框补(默认1像素)        private int padding = 1;        public int Padding        {            get { return padding; }            set { padding = value; }        }        #endregion        #region 是否输出燥点(默认不输出)        private bool chaos = true;        public bool Chaos        {            get { return chaos; }            set { chaos = value; }        }        #endregion        #region 输出燥点的颜色(默认灰色)        private Color chaosColor = Color.LightGray;        public Color ChaosColor        {            get { return chaosColor; }            set { chaosColor = value; }        }        #endregion        #region 自定义背景色(默认白色)        private Color backgroundColor = Color.White;        public Color BackgroundColor        {            get { return backgroundColor; }            set { backgroundColor = value; }        }        #endregion        #region 自定义随机颜色数组        private Color[] colors =        {            Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown,            Color.DarkCyan, Color.Purple        };        public Color[] Colors        {            get { return colors; }            set { colors = value; }        }        #endregion        #region 自定义字体数组        private string[] fonts = {
    "Arial", "Georgia"};        public string[] Fonts        {            get { return fonts; }            set { fonts = value; }        }        #endregion        #region 自定义随机码字符串序列(使用逗号分隔)        private string codeSerial = "0,1,2,3,4,5,6,7,8,9";        // string codeSerial = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";       // string codeSerial = "殃,央,鸯,秧,杨,扬,佯,疡,羊,洋,阳,氧,仰,痒,养,样,漾,邀,腰,妖,瑶,摇,尧,遥,窑,谣,姚,咬,舀,药,要,耀,椰,噎,耶,爷,野,冶,也,页,掖,业,叶,曳,腋,夜,液,一,壹,医,揖,铱,依,伊,衣,颐,夷,遗,移,仪,胰,疑,沂,宜,姨,彝,椅,蚁,倚,已,乙,矣,以,艺,抑,易,邑,屹,亿,役,臆,逸,肄,疫,亦,裔,意,毅,忆,义,益,溢,诣,议,谊,译,异,翼,翌,绎,茵,荫,因,殷,音,阴,姻,吟,银,淫,寅,饮,尹,引,隐,印,英,樱,婴,鹰,应,缨,莹,萤,营,荧,蝇,迎,赢,盈,影,颖,硬,映,哟,拥,佣,臃,痈,庸,雍,踊,蛹,咏,泳,涌,永,恿,勇,用,幽,优,悠,忧,尤,由,邮,铀,犹,油,游,酉,有,友,右,佑,釉,诱,又,幼,迂,淤,于,盂,榆,虞,愚,舆,余,俞,逾,鱼,愉,渝,渔,隅,予,娱,雨,与,屿,禹,株,蛛,朱,猪,诸,诛,逐,竹,烛,煮,拄,瞩,嘱,主,著,柱,助,蛀,贮,铸,筑,住,注,祝,驻,抓,爪,拽,专,砖,转,撰,赚,篆,桩,庄,装,妆,撞,壮,状,椎,锥,追,赘,坠,缀,谆,准,捉,拙,卓,桌,琢,茁,酌,啄,着,灼,浊,兹,咨,资,姿,滋,淄,孜,紫,仔,籽,滓,子,自,渍,字,鬃,棕,踪,宗,综,总,纵,邹,走,奏,揍,租,足,卒,族,祖,诅,阻,组,钻,纂,嘴,醉,最,罪,尊,遵,昨,左,佐,柞,做,作,坐,座";        public string CodeSerial        {            get { return codeSerial; }            set { codeSerial = value; }        }        #endregion        //产生波形滤镜效果        #region 产生波形滤镜效果        private const double PI = 3.1415926535897932384626433832795;        private const double PI2 = 6.283185307179586476925286766559;        /**/        /// 
        /// 正弦曲线Wave扭曲图片（Edit By 51aspx.com）        /// 
        /// 图片路径        /// 如果扭曲则选择为True        /// 波形的幅度倍数，越大扭曲的程度越高，一般为3        /// 波形的起始相位，取值区间[0-2*PI)        /// 
              public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)        {            System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);            // 将位图背景填充为白色            System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp);            graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height);            graph.Dispose();            double dBaseAxisLen = bXDir ? (double) destBmp.Height : (double) destBmp.Width;            for (int i = 0; i < destBmp.Width; i++)            {                for (int j = 0; j < destBmp.Height; j++)                {                    double dx = 0;                    dx = bXDir ? (PI2*(double) j)/dBaseAxisLen : (PI2*(double) i)/dBaseAxisLen;                    dx += dPhase;                    double dy = Math.Sin(dx);                    // 取得当前点的颜色                    int nOldX = 0, nOldY = 0;                    nOldX = bXDir ? i + (int) (dy*dMultValue) : i;                    nOldY = bXDir ? j : j + (int) (dy*dMultValue);                    System.Drawing.Color color = srcBmp.GetPixel(i, j);                    if (nOldX >= 0 && nOldX < destBmp.Width                        && nOldY >= 0 && nOldY < destBmp.Height)                    {                        destBmp.SetPixel(nOldX, nOldY, color);                    }                }            }            return destBmp;        }        #endregion        #region 生成校验码图片        public Bitmap CreateImageCode(string code)        {            int fSize = FontSize;            int fWidth = fSize + Padding;            int imageWidth = (int) (code.Length*fWidth) + 4 + Padding*2;            int imageHeight = fSize*2 + Padding;            System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight);            Graphics g = Graphics.FromImage(image);            g.Clear(BackgroundColor);            Random rand = new Random();            //给背景添加随机生成的燥点            if (this.Chaos)            {                Pen pen = new Pen(ChaosColor, 0);                int c = Length*10;                for (int i = 0; i < c; i++)                {                    int x = rand.Next(image.Width);                    int y = rand.Next(image.Height);                    g.DrawRectangle(pen, x, y, 1, 1);                }            }            int left = 0, top = 0, top1 = 1, top2 = 1;            int n1 = (imageHeight - FontSize - Padding*2);            int n2 = n1/4;            top1 = n2;            top2 = n2*2;            Font f;            Brush b;            int cindex, findex;            #region 随机字体和颜色的验证码字符            for (int i = 0; i < code.Length; i++)            {                cindex = rand.Next(Colors.Length - 1);                findex = rand.Next(Fonts.Length - 1);                f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);                b = new System.Drawing.SolidBrush(Colors[cindex]);                if (i%2 == 1)                {                    top = top2;                }                else                {                    top = top1;                }                left = i*fWidth;                g.DrawString(code.Substring(i, 1), f, b, left, top);            }            //画一个边框 边框颜色为Color.Gainsboro            g.DrawRectangle(new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1);            g.Dispose();            //产生波形            //image = TwistImage(image, true, 8, 4);            return image;        }        #endregion        //将创建好的图片输出到页面        public void CreateImageOnPage(string code, HttpContext context)        {            System.IO.MemoryStream ms = new System.IO.MemoryStream();            Bitmap image = this.CreateImageCode(code);            image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);            context.Response.ClearContent();            context.Response.ContentType = "image/Jpeg";            context.Response.BinaryWrite(ms.GetBuffer());            ms.Close();            ms = null;            image.Dispose();            image = null;        }        #endregion        #region 生成随机字符码        public string CreateVerifyCode(int codeLen)        {            if (codeLen == 0)            {                codeLen = Length;            }            string[] arr = CodeSerial.Split(',');            string code = "";            int randValue = -1;            Random rand = new Random(unchecked((int) DateTime.Now.Ticks));            for (int i = 0; i < codeLen; i++)            {                randValue = rand.Next(0, arr.Length - 1);                code += arr[randValue];            }            return code;        }        public string CreateVerifyCode()        {            return CreateVerifyCode(0);        }        #endregion    }}

效果:

说明:在这只是记录下东西,好多东西不是自己的,只是为了要用到时方便...