.net生成随机验证码图片

/// <summary>

        /// 自定义图片验证码函数

        /// 该函数将生成一个图片验证码，并将生成的code存放于Session["VerifyCode"]变量内。

        /// </summary>

        /// <param name="codeLength">验证码长度</param>

        /// <param name="codeFontsize">字体大小</param>

        /// <value>该函数将生成一个图片验证码，并把生成的code存放于Session["VerifyCode"]变量内</value>

        public static void VerifyCode(int codeLength, int codeFontsize)

        {

            double PI = 6.283185307179586476925286766559;

            int m_ImgWidth = (int)(codeLength * (codeFontsize + 2.5)) + ;  //图像宽度

            int m_ImgHeight = codeFontsize *  + ;   //图像高度

            string[] m_Fonts = { "Arial", "Georgia" }; //随机字体

            string[] m_StrarraySource ={"","","","","","","","",

                             "A","B","C","D","E","F","G","H","J","K","M","N",

                             "P","Q","R","S","T","U","V","W","X","Y","Z",

                             "a","b","c","d","e","f","g","h","j","k","m","n",

                             "p","q","r","s","t","u","v","w","x","y","z"};    //随机字符所包含范围

            Color[] m_ColorarraySource ={Color.Maroon,Color.Red,Color.IndianRed,Color.Tomato,Color.OrangeRed,

                             Color.SaddleBrown,Color.Goldenrod,Color.Olive,Color.OliveDrab,Color.ForestGreen,

                             Color.Green,Color.SeaGreen,Color.LightSeaGreen,Color.Teal,Color.CadetBlue,

                             Color.SteelBlue,Color.DodgerBlue,Color.CornflowerBlue,Color.Blue,

                             Color.MediumSlateBlue,Color.BlueViolet,Color.DarkViolet,Color.Fuchsia,

                             Color.DeepPink,Color.Crimson};//随机字符颜色所包含范围

            string m_StrCode = "";         //用于存放生成的随机数

            Random m_StrRandom = new Random();

            for (int i = ; i < codeLength; i++)

            {

                m_StrCode += m_StrarraySource[m_StrRandom.Next(, m_StrarraySource.Length)]; //生成随机字符串

            }

            Bitmap m_BitmapImg = new Bitmap(m_ImgWidth, m_ImgHeight);//定义一个画板

            Graphics m_GraphicsSl = Graphics.FromImage(m_BitmapImg);//在画板上定义绘图的实例

            Rectangle m_RectangleJx = new Rectangle(, , m_ImgWidth, m_ImgHeight);//定义一个矩形

            m_GraphicsSl.FillRectangle(new SolidBrush(Color.White), m_RectangleJx);//填充矩形

            //bPsl.DrawString(code, new Font("新宋体", 12), new SolidBrush(Color.Black), bPjx);//在矩形内画出字符串

            for (int i = ; i < m_StrCode.Length; i++)

            {

                m_GraphicsSl.DrawString(m_StrCode.Substring(i, ), new Font(m_Fonts[m_StrRandom.Next(, m_Fonts.Length)].ToString(), codeFontsize, FontStyle.Bold), new SolidBrush(Color.FromKnownColor(m_ColorarraySource[m_StrRandom.Next(, m_ColorarraySource.Length)].ToKnownColor())), i * (codeFontsize + ) + , Convert.ToBoolean(i % ) ? (m_ImgHeight - codeFontsize - ) /  : (m_ImgHeight - codeFontsize - ) / );

            }

            //生成干扰

            Random m_RandomR = new Random();

            //生成干扰线条

            Pen pen = new Pen(new SolidBrush(Color.FromKnownColor(m_ColorarraySource[m_StrRandom.Next(, m_ColorarraySource.Length)].ToKnownColor())), );

            for (int i = ; i < m_ImgHeight / ; i++)

            {

                m_GraphicsSl.DrawLine(pen, new Point(m_RandomR.Next(, m_ImgWidth), m_RandomR.Next(, m_ImgHeight)), new Point(m_RandomR.Next(, m_ImgWidth), m_RandomR.Next(, m_ImgHeight)));

            }

            //生成干扰点

            //SolidBrush m_SolidbrushP2 = new SolidBrush(ColorTranslator.FromHtml("#f0f0f0"));//干扰点颜色

            SolidBrush m_SolidbrushP2 = new SolidBrush(Color.FromKnownColor(m_ColorarraySource[m_StrRandom.Next(, m_ColorarraySource.Length)].ToKnownColor()));//干扰点颜色

            for (int i = ; i < m_ImgWidth / ; i++)

            {

                for (int j = ; j < m_ImgHeight / ; j++)

                {

                    m_GraphicsSl.FillEllipse(m_SolidbrushP2, m_RandomR.Next(m_ImgWidth), j, m_RandomR.Next(), );//在矩形内画干扰点

                }

            }

            m_GraphicsSl.Dispose();

            //正弦曲线Wave扭曲图片

            Bitmap m_TempBmp = new Bitmap(m_ImgWidth, m_ImgHeight);

            // 将位图背景填充为白色

            Graphics m_Graph = Graphics.FromImage(m_TempBmp);

            m_Graph.FillRectangle(new SolidBrush(Color.White), , , m_ImgWidth, m_ImgHeight);

            m_Graph.Dispose();

            for (int i = ; i < m_ImgWidth; i++)

            {

                for (int j = ; j < m_ImgHeight; j++)

                {

                    double m_dx = (PI * (double)j) / (double)m_ImgHeight + ;

                    double m_dy = Math.Sin(m_dx);

                    // 取得当前点的颜色

                    int m_nOldX = , m_nOldY = ;

                    m_nOldX = i + (int)(m_dy * );

                    m_nOldY = j;

                    Color m_color = m_BitmapImg.GetPixel(i, j);

                    if (m_nOldX >=  && m_nOldX < m_ImgWidth && m_nOldY >=  && m_nOldY < m_ImgHeight)

                    {

                        m_TempBmp.SetPixel(m_nOldX, m_nOldY, m_color);

                    }

                }

            }

            m_BitmapImg = m_TempBmp;

            //生成边框

            Graphics m_GraphicsSl2 = Graphics.FromImage(m_BitmapImg);//在画板上定义绘图的实例

            m_GraphicsSl2.DrawRectangle(new Pen(Color.FromKnownColor(m_ColorarraySource[m_StrRandom.Next(, m_ColorarraySource.Length)].ToKnownColor()), ), , , m_ImgWidth - , m_ImgHeight - );

            //bPimg.Save(fullfilename, System.Drawing.Imaging.ImageFormat.Gif);//保存为文件

            m_BitmapImg.Save(System.Web.HttpContext.Current.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);//将图片显示出来

            //释放资源

            m_GraphicsSl.Dispose();

            m_BitmapImg.Dispose();

            //返回值  //将字符串保存到Session中，以便需要时进行验证

            System.Web.HttpContext.Current.Session["VerifyCode"] = m_StrCode;

        }

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Drawing;

namespace FeiBoLaiTe.Admin

{

    public partial class Yanzhengma : System.Web.UI.Page

    {

        protected void Page_Load(object sender, EventArgs e)

        {

            if (!Page.IsPostBack)

            {

                GenImg(GenCode());

            }

        }

        private string GenCode(int num)

        {

            string[] source ={"","","","","","","","","","",

                         "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 code = "";

            Random rd = new Random();

            for (int i = ; i < num; i++)

            {

                code += source[rd.Next(, source.Length)];

            }

            return code;

        }

        //生成图片

        private void GenImg(string code)

        {

            Bitmap myPalette = new Bitmap(, );//定义一个画板

            Graphics gh = Graphics.FromImage(myPalette);//在画板上定义绘图的实例

            Rectangle rc = new Rectangle(, , , );//定义一个矩形

            gh.FillRectangle(new SolidBrush(Color.CornflowerBlue), rc);//填充矩形

            gh.DrawString(code, new Font("宋体", ), new SolidBrush(Color.White), rc);//在矩形内画出字符串

            myPalette.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);//将图片显示出来

            Session["code"] = code;//将字符串保存到Session中，以便需要时进行验证

            gh.Dispose();

            myPalette.Dispose();

        }

    }

}

private string GenerateCheckCode()

        {

            int number;

            string strCode = string.Empty;

            //随机种子

            //Random random = new Random();

            //for (int i = 0; i < 4; i++) //验证码长度为4

            //{

            //    //随机整数

            //    number = random.Next();

            //    //字符从0-9，A-Z中产生，对应的ASCII码为48-57，65-90

            //    number = number % 36;

            //    if (number < 10)

            //    {

            //        number += 48;

            //    }

            //    else

            //    {

            //        number += 55;

            //    }

            //    strCode += ((char)number).ToString();

            //}

              //产生随机字符串

            strCode =  GenCode();

            //将字符串保存在Cookies

            Response.Cookies.Add(new HttpCookie("gst_checkCode", strCode));

            return strCode;

        }

        private string GenCode(int num)

        {

            string[] source ={"","","","","","","","","","",

                                "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 code = "";

            Random rd = new Random();

            for (int i = ; i < num; i++)

            {

                code += source[rd.Next(, source.Length)];

            }

            return code;

        }

        //生成图片

        private void CreateCheckCodeImage(string checkCode)

        {

            //若检验码为空，则直接返回

            if (checkCode == null || checkCode.Trim() == string.Empty)

                return;

            //根据验证码长度确定输出图片的长度

            System.Drawing.Bitmap image = new Bitmap((int)Math.Ceiling(float.Parse((checkCode.Length * ).ToString())), );

            //创建Graphics对象

            System.Drawing.Graphics g = Graphics.FromImage(image);

            //生成随机数种子

            Random random = new Random();

            //清除图片背景颜色

            g.Clear(Color.White);

            //画背景图片的噪音线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);

                //用银色线画出噪音线

                g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);

            }

            //输出图片中校验码的字体:12号Arial,粗斜体

            Font font = new Font("Arial", , FontStyle.Bold);

            //线性渐变画刷

            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(, , image.Width, image.Width), Color.Blue, Color.Purple, 1.2f, true);

            g.DrawString(checkCode, font, brush, , );

            //画图片的前景噪点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()));

            }

            //画图片段边框线

            g.DrawRectangle(new Pen(Color.SaddleBrown), , , image.Width - , image.Height - );

            //创建内存流用于输出图片

            System.IO.MemoryStream ms = new System.IO.MemoryStream();

            //图片格式指定为png

            image.Save(ms, System.Drawing.Imaging.ImageFormat.Png);

            //清除缓冲区流中的所有输出

            Response.ClearContent();

            //输出流的Http Mime类型设置为"image/Png"

            Response.ContentType = "image/Png";

            //输出图片的二进制流

            Response.BinaryWrite(ms.ToArray()); 

            //释放Bitmap和Graphics对象

            g.Dispose();

            image.Dispose();

        }

巴特西

.net生成随机验证码图片

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