生成验证码图象文件

using System;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using System.Text;

namespace HRManager.CommonComponent
{
    /// <summary>
    /// 生成验证码图象类
    /// </summary>
    public class ValidateCode
    {
        private const int CODELEN = 4;  //4位验证码
       
        public string code;             //生成的验证码
        public string imgFilePath ;     //生成的图象路径
        public string imgFileName;      //生成的图象文件名

        /// <summary>
        /// 构造函数，得到保存图象的路径
        /// </summary>
        public ValidateCode(string imgFilePath)
        {
            this.imgFilePath = imgFilePath;
        }

        /// <summary>
        /// 析构函数，删除生成的图象文件
        /// </summary>
        ~ValidateCode()
        {
            File.Delete(this.imgFilePath+this.imgFileName); //使用File的Delete静态方法，删除临时图象
        }

        /// <summary>
        /// 生成验证码图象文件，并存储在服务器中
        /// </summary>
        public void GenerateCodeImage()
        {
            this.GetCode();
            Bitmap img = null;
            Graphics g = null;           

            int gHeight = code.Length * 12;
            img = new Bitmap(gHeight, 25);
            g = Graphics.FromImage(img);

            g.Clear(Color.AliceBlue);                       //背景颜色           
            Font font = new Font("Arial Black", 10);        //文字字体
            SolidBrush brush = new SolidBrush(Color.Black); //文字颜色
          
            g.DrawString(this.code, font, brush, 3, 3);
           
            this.imgFileName = this.code + ".Png";
            img.Save(this.imgFilePath+this.imgFileName, ImageFormat.Png);

            g.Dispose();
            img.Dispose();
        }

        /// <summary>
        /// 生成随即的四位字母、数字混合串
        /// </summary>
        /// <returns>四位字母、数字混合串</returns>
        public void GetCode()
        {
            char[] allChars = new char[]{
                '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'
            };
           
            Random rand = new Random();

            for (int i = 0; i < CODELEN; i++)
            {
                rand = new Random((i+1) * (int)DateTime.Now.Ticks);
                this.code+= allChars[rand.Next(allChars.Length - 1)];
            }
        }     
    }
}

 

--------------------------------

应用

 

     //“验证码”，放在隐藏文本框TextBoxValiCode2中
        ValidateCode vcode = new ValidateCode(Request.PhysicalApplicationPath + "");
        vcode.GenerateCodeImage();
        ImageValiCode.ImageUrl = vcode.imgFileName;
        TextBoxValiCode2.Text =   vcode.code;

 

 

----------------------------------------方法二 参考 未验证

验证码实现方法

Code
    protected void Page_Load(object sender, EventArgs e)
    {
         string checkCode = CreateRandomCode(4);
          Session["CheckCode"] = checkCode;
          CreateImage(checkCode);
    }
     private string CreateRandomCode(int codeCount)
    {

        // 函数功能:产生数字和字符混合的随机字符串
        string allChar = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
        char[] allCharArray = allChar.ToCharArray();
        string randomCode = "";
        Random rand = new Random();
        for (int i = 0; i < codeCount; i++)
        {
           int r=rand.Next(61);
           randomCode+=allCharArray.GetValue(r);
        }
         return randomCode;
        
     }
         

    private void CreateImage(string checkCode)
    {

        // 生成图象验证码函数
       int iwidth = (int)(checkCode.Length * 11.5);
        System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 20);
        Graphics g = Graphics.FromImage(image);
        Font f = new System.Drawing.Font("Arial", 10, System.Drawing.FontStyle.Bold);
        Brush b = new System.Drawing.SolidBrush(Color.Azure);//字母白色
        //g.FillRectangle(new System.Drawing.SolidBrush(Color.Blue),0,0,image.Width, image.Height);
        g.Clear(Color.Brown);//背景灰色
        g.DrawString(checkCode, f, b, 3, 3);

        Pen blackPen = new Pen(Color.Black, 0);
        Random rand = new Random();
        System.IO.MemoryStream ms = new System.IO.MemoryStream();
        image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
        Response.ClearContent();
        Response.ContentType = "image/Jpeg";
        Response.BinaryWrite(ms.ToArray());
        g.Dispose();
        image.Dispose();
    }