验证码详解,高手飘过

本来想偷懒,在网络找验证码类,可是没找到自己需要的;有点伤心,看了一下别人写的,然后开始花了一个多小时解决问题, 放在这里 给我和不懂的盆友们查看备用  主要就以代码解释为主了,楼主语文重来不及格, 看code

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;

namespace Tools
{
    public class CheakCode
    {
        #region 构造

        /// <summary>
/// 验证码类,随机生成4到5个字符
/// <example>
///CheakCode cheakcode = new CheakCode();
///
///Response.ClearContent();
///
///Response.ContentType = "image/Gif";
///
///Response.BinaryWrite(cheakcode.GetImgWithValidateCode().ToArray());
///
///cheakcode = null;
/// </example>
/// </summary>
        public CheakCode() { }

        public CheakCode(string codeStr, int h, int w, int codeNum, int fSize)
        {
            this.codeStr = codeStr;
            this.height = h;
            this.width = w;
            this.codeNum = codeNum;
            this.fontSize = fSize;
        }

        public CheakCode(string codeStr)
        {
            this.codeStr = codeStr;
        }

        public CheakCode(int fSize, string codeStr)
        {
            this.codeStr = codeStr;
            this.fontSize = fSize;
        }

        public CheakCode(string codeStr, int codeNum)
        {
            this.codeNum = codeNum;
            this.codeStr = codeStr;
        }

        public CheakCode(int w, int h)
        {
            this.height = h;
            this.width = w;
        }

        #endregion 构造

        #region 属性

        private int _width = 100;

        /// <summary>
/// 验证码彩条宽度
/// </summary>
        public int width { get { return this._width; } set { this._width = value; } }

        private int _height = 40;

        /// <summary>
/// 验证码彩条高度
/// </summary>
        public int height { get { return this._height; } set { this._height = value; } }

        private int _codeNum = new Random().Next(4, 6);

        /// <summary>
/// 验证码彩条需要产生的个数
/// </summary>
        public int codeNum { get { return this._codeNum; } set { this._codeNum = value; } }

        private string _codeStr = Guid.NewGuid().ToString().Replace("-", "");// "ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789";

        /// <summary>
/// 验证码字符串 默认就拿Guid 产生字符
/// </summary>
        public string codeStr { get { return this._codeStr; } set { this._codeStr = value; } }

        private int _fontSize = 15;

        /// <summary>
/// 验证码彩条字体大小
/// </summary>
        public int fontSize { get { return this._fontSize; } set { this._fontSize = value; } }

        /// <summary>
/// 彩条字体,我这里定义了一些,使用中随机抽取一种
/// </summary>
        private String[] fontFamily ={ "Arial", "Verdana", "Comic Sans MS", "Impact", "Haettenschweiler",
                                         "Lucida Sans Unicode", "Garamond", "Courier New", "Book Antiqua", "Arial Narrow" };

        /// <summary>
/// 产生验证码字符串
/// </summary>
        public string GetValidateCode
        {
            get
            {
                Random rd = new Random(); //创建随机数对象

                string tempStr = null;
                for (int i = 0; i < codeNum; i++)
                {
                    tempStr = tempStr + this.codeStr[rd.Next(this._codeStr.Length - 1)];
                }
                return tempStr;
            }
            private set { }
        }

        #endregion 属性

        /// <summary>
/// 随机字符串，随机颜色背景，和随机线条产生的Image
/// 返回 MemoryStream
/// </summary>
/// <returns>MemoryStream</returns>
        public MemoryStream GetImgWithValidateCode()
        {
            //声明位图
            Bitmap bitMap = null;

            ///画笔
            Graphics gph = null;
            using (MemoryStream memStream = new MemoryStream())
            {
                Random random = new Random();
                int fontWidth = (int)Math.Round(this.width / (this.codeNum + 2) / 1.0);  //这里主要是适应字符的字符,让其能全部显示出来
                int fontHeight = (int)Math.Round(this.height / 1.0);
                this.fontSize = fontWidth <= fontHeight ? fontWidth : fontHeight; //取字体大小中间值
                using (bitMap = new Bitmap(this.width, this.height))
                {
                    gph = Graphics.FromImage(bitMap);
                    gph.Clear(GetControllableColor(200));
                    PointF Cpoint1 = new PointF(5, 5);
                    int x1 = 0, y1 = 0;
                    ///通过循环控制每一个字符
                    for (int i = 0; i < this.GetValidateCode.Length; i++)
                    {
                        //随机字符位置
                        x1 = random.Next(10) + 15 * i;
                        y1 = random.Next(bitMap.Height / 4);
                        Cpoint1 = new PointF(x1, y1);
                        SolidBrush solidBrush = new SolidBrush(Color.FromArgb(random.Next(100), random.Next(100), random.Next(100)));  //调整颜色,使其文字能看见
                        Font textFont = new Font(this.fontFamily[random.Next(this.fontFamily.Length - 1)], this.fontSize, FontStyle.Bold);
                        gph.TranslateTransform(10, 0);
                        Matrix transform = gph.Transform;
                        if (i % 2 == 0)  //这里我做了大小写处理 true 大写了
                        {
                            gph.DrawString(this.GetValidateCode.Substring(i, 1).ToUpper(), textFont, solidBrush, Cpoint1);  //写字符
                        }
                        else
                        {
                            gph.DrawString(this.GetValidateCode.Substring(i, 1), textFont, solidBrush, Cpoint1);  //写字符
                        }

                        gph.ResetTransform(); //重置矩阵
                    }
                    gph.DrawRectangle(new Pen(Color.Black, 2), 0, 0, bitMap.Width - 1, bitMap.Height - 1);// //画图片的边框线
                    try
                    {
                        bitMap.Save(memStream, ImageFormat.Gif);//保存内存流
                    }
                    catch (Exception ex)
                    {
                        throw ex;
                    }
                    finally
                    {
                        bitMap.Dispose();
                        random = null;
                        gph.Dispose();
                    }
                    return memStream;
                }
            }
        }

        /// <summary>
/// 产生随机颜色(R,G,B)
/// </summary>
/// <param name="colorBase"></param>
/// <returns>背景色</returns>
        private Color GetControllableColor(int colorBase)
        {
            Color color = Color.Black;
            if (colorBase > 200)
            {
                return color;
            }
            Random random = new Random();
            color = Color.FromArgb(random.Next(56) + colorBase, random.Next(56) + colorBase, random.Next(56) + colorBase);
            random = null;
            return color;
        }

        /// <summary>
/// 判断验证码是否正确
/// </summary>
/// <param name="inputValCode">待判断的验证码</param>
/// <returns>正确返回 true,错误返回 false</returns>
        public bool IsRight(string inputValCode)
        {
            if (this.GetValidateCode.ToUpper().Equals(inputValCode.ToUpper()))//无论输入大小写都转换为大些判断
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}