验证码

实现代码

public void ValidateImg()
       {
           VerifyCodeSugar v = new VerifyCodeSugar();
 
           //是否随机字体颜色
           v.SetIsRandomColor = true;
           //随机码的旋转角度
           v.SetRandomAngle = 4;
           //文字大小
           v.SetFontSize = 15;
           //背景色
           //v.SetBackgroundColor
           //前景噪点数量
           //v.SetForeNoisePointCount = 3;
           //v.SetFontColor =Color.Red;
           //...还有更多设置不介绍了
 
           var questionList = new Dictionary<string, string>()
           {
 
               {"1+1=？","2"},
               {"喜羊羊主角叫什么名字？","喜羊羊" },
               {"【我爱你】中间的那个字？","爱" },
           };
 
           var questionItem = v.GetQuestion();//不赋值为随机验证码 例如： 1*2=? 这种
 
           //指定验证文本
           //v.SetVerifyCodeText
 
           v.SetVerifyCodeText = questionItem.Key;
 
           Session["VerifyCode"] = questionItem.Value;
 
           //输出图片
           v.OutputImage(System.Web.HttpContext.Current.Response);
 
       }

封装类

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Text;
using System.Web;
 
namespace Idea.Models
{
 
    /// <summary>
    /// 验证码类
    /// </summary>
    public class VerifyCodeSugar
    {
        private Random objRandom = new Random();
 
        #region setting
 
        /// <summary>
        /// //验证码长度
        /// </summary>
        public int SetLength = 4;
        /// <summary>
        /// 验证码字符串
        /// </summary>
        public string SetVerifyCodeText { get; set; }
        /// <summary>
        /// 是否加入小写字母
        /// </summary>
        public bool SetAddLowerLetter = false;
        /// <summary>
        /// 是否加入大写字母
        /// </summary>
        public bool SetAddUpperLetter = false;
        /// <summary>
        /// 字体大小
        /// </summary>
        public int SetFontSize = 18;
        /// <summary>
        ///  //字体颜色
        /// </summary>
        public Color SetFontColor = Color.Blue;
        /// <summary>
        /// 字体类型
        /// </summary>
        public string SetFontFamily = "Verdana";
        /// <summary>
        /// 背景色
        /// </summary>
        public Color SetBackgroundColor = Color.AliceBlue;
        /// <summary>
        /// 前景噪点数量
        /// </summary>
        public int SetForeNoisePointCount = 2;
        /// <summary>
        /// 随机码的旋转角度
        /// </summary>
        public int SetRandomAngle = 40;
 
        /// <summary>
        /// 是否随机字体颜色
        /// </summary>
        public bool SetIsRandomColor = false;
        /// <summary>
        /// 图片宽度
        /// </summary>
        private int SetWith
        {
            get
            {
                return this.SetVerifyCodeText.Length * SetFontSize;
            }
        }
        /// <summary>
        /// 图片高度
        /// </summary>
        private int SetHeight
        {
            get
            {
                return Convert.ToInt32((60.0 / 100) * SetFontSize + SetFontSize);
            }
        }
        #endregion
 
        #region Constructor Method
        public VerifyCodeSugar()
        {
            this.GetVerifyCodeText();
        }
        #endregion
 
        #region Private Method
        /// <summary>
        /// 得到验证码字符串
        /// </summary>
        private void GetVerifyCodeText()
        {
 
            //没有外部输入验证码时随机生成
            if (String.IsNullOrEmpty(this.SetVerifyCodeText))
            {
                StringBuilder objStringBuilder = new StringBuilder();
 
                //加入数字1-9
                for (int i = 1; i <= 9; i++)
                {
                    objStringBuilder.Append(i.ToString());
                }
 
                //加入大写字母A-Z，不包括O
                if (this.SetAddUpperLetter)
                {
                    char temp = ' ';
 
                    for (int i = 0; i < 26; i++)
                    {
                        temp = Convert.ToChar(i + 65);
 
                        //如果生成的字母不是'O'
                        if (!temp.Equals('O'))
                        {
                            objStringBuilder.Append(temp);
                        }
                    }
                }
 
                //加入小写字母a-z，不包括o
                if (this.SetAddLowerLetter)
                {
                    char temp = ' ';
 
                    for (int i = 0; i < 26; i++)
                    {
                        temp = Convert.ToChar(i + 97);
 
                        //如果生成的字母不是'o'
                        if (!temp.Equals('o'))
                        {
                            objStringBuilder.Append(temp);
                        }
                    }
                }
 
                //生成验证码字符串
                {
                    int index = 0;
 
                    for (int i = 0; i < SetLength; i++)
                    {
                        index = objRandom.Next(0, objStringBuilder.Length);
 
                        this.SetVerifyCodeText += objStringBuilder[index];
 
                        objStringBuilder.Remove(index, 1);
                    }
                }
            }
        }
 
        /// <summary>
        /// 得到验证码图片
        /// </summary>
        private Bitmap GetVerifyCodeImage()
        {
            Bitmap result = null;
 
            //创建绘图
            result = new Bitmap(SetWith, SetHeight);
 
            using (Graphics objGraphics = Graphics.FromImage(result))
            {
                objGraphics.SmoothingMode = SmoothingMode.HighQuality;
 
                //清除整个绘图面并以指定背景色填充
                objGraphics.Clear(this.SetBackgroundColor);
 
                //创建画笔
                using (SolidBrush objSolidBrush = new SolidBrush(this.SetFontColor))
                {
                    this.AddForeNoisePoint(result);
 
                    this.AddBackgroundNoisePoint(result, objGraphics);
 
                    //文字居中
                    StringFormat objStringFormat = new StringFormat(StringFormatFlags.NoClip);
 
                    objStringFormat.Alignment = StringAlignment.Center;
                    objStringFormat.LineAlignment = StringAlignment.Center;
 
                    //字体样式
                    Font objFont = new Font(this.SetFontFamily, objRandom.Next(this.SetFontSize - 3, this.SetFontSize), FontStyle.Regular);
 
                    //验证码旋转，防止机器识别
                    char[] chars = this.SetVerifyCodeText.ToCharArray();
 
                    for (int i = 0; i < chars.Length; i++)
                    {
                        //转动的度数
                        float angle = objRandom.Next(-this.SetRandomAngle, this.SetRandomAngle);
 
                        objGraphics.TranslateTransform(12, 12);
                        objGraphics.RotateTransform(angle);
                        objGraphics.DrawString(chars[i].ToString(), objFont, objSolidBrush, -2, 2, objStringFormat);
                        objGraphics.RotateTransform(-angle);
                        objGraphics.TranslateTransform(2, -12);
                    }
                }
            }
 
            return result;
        }
 
        /// <summary>
        /// 添加前景噪点
        /// </summary>
        /// <param name="objBitmap"></param>
        private void AddForeNoisePoint(Bitmap objBitmap)
        {
            for (int i = 0; i < objBitmap.Width * this.SetForeNoisePointCount; i++)
            {
                objBitmap.SetPixel(objRandom.Next(objBitmap.Width), objRandom.Next(objBitmap.Height), this.SetFontColor);
            }
        }
 
        /// <summary>
        /// 添加背景噪点
        /// </summary>
        /// <param name="objBitmap"></param>
        /// <param name="objGraphics"></param>
        private void AddBackgroundNoisePoint(Bitmap objBitmap, Graphics objGraphics)
        {
            using (Pen objPen = new Pen(Color.Azure, 0))
            {
                for (int i = 0; i < objBitmap.Width * 2; i++)
                {
                    objGraphics.DrawRectangle(objPen, objRandom.Next(objBitmap.Width), objRandom.Next(objBitmap.Height), 1, 1);
                }
            }
 
        }
 
        /// <summary>
        /// 获取随机颜色
        /// </summary>
        /// <returns></returns>
        private Color GetRandomColor()
        {
            Random RandomNum_First = new Random((int)DateTime.Now.Ticks);
            // 对于C#的随机数，没什么好说的
            System.Threading.Thread.Sleep(RandomNum_First.Next(50));
            Random RandomNum_Sencond = new Random((int)DateTime.Now.Ticks);
            // 为了在白色背景上显示，尽量生成深色
            int int_Red = RandomNum_First.Next(256);
            int int_Green = RandomNum_Sencond.Next(256);
            int int_Blue = (int_Red + int_Green > 400) ? 0 : 400 - int_Red - int_Green;
            int_Blue = (int_Blue > 255) ? 255 : int_Blue;
            return Color.FromArgb(int_Red, int_Green, int_Blue);
        }
        #endregion
 
        #region Public Method
        /// <summary>
        /// 输出验证码图片
        /// </summary>
        /// <param name="objHttpResponse">Http响应实例</param>
        /// <returns>输出是否成功</returns>
        public bool OutputImage(HttpResponse objHttpResponse)
        {
            bool result = false;
            if (this.SetIsRandomColor)
            {
                this.SetFontColor = GetRandomColor(); ;
            }
 
            using (Bitmap objBitmap = this.GetVerifyCodeImage())
            {
                if (objBitmap != null)
                {
                    using (MemoryStream objMS = new MemoryStream())
                    {
                        objBitmap.Save(objMS, ImageFormat.Jpeg);
 
                        HttpContext.Current.Response.ClearContent();
                        HttpContext.Current.Response.ContentType = "image/Jpeg";
                        HttpContext.Current.Response.BinaryWrite(objMS.ToArray());
                        HttpContext.Current.Response.Flush();
                        HttpContext.Current.Response.End();
 
                        result = true;
                    }
                }
            }
 
            return result;
        }
 
        /// <summary>
        /// 获取问题
        /// </summary>
        /// <param name="questionList">默认数字加减验证</param>
        /// <returns></returns>
        public KeyValuePair<string, string> GetQuestion(Dictionary<string, string> questionList = null)
        {
            if (questionList == null)
            {
                questionList = new Dictionary<string, string>();
                var operArray = new string[] { "+", "*", "num" };
                var left = objRandom.Next(0, 10);
                var right = objRandom.Next(0, 10);
                var oper = operArray[objRandom.Next(0, operArray.Length)];
                if (oper == "+")
                {
                    string key = string.Format("{0}+{1}=?", left, right);
                    string val = (left + right).ToString();
                    questionList.Add(key, val);
                }
                else if (oper == "*")
                {
                    string key = string.Format("{0}×{1}=?", left, right);
                    string val = (left * right).ToString();
                    questionList.Add(key, val);
                }
                else
                {
                    var num = objRandom.Next(1000, 9999); ;
                    questionList.Add(num.ToString(), num.ToString());
                }
            }
            return questionList.ToList()[objRandom.Next(0, questionList.Count)];
        }
        #endregion
    }
 
}

/// <summary>
/// 生成验证码图片
/// </summary>
public static string build(HttpResponseBase response)
{
string checkCode = GenerateCheckCode();
if (checkCode == null || checkCode.Trim() == String.Empty)
return "";
//控制图片大小(长,宽)
System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
Graphics g = Graphics.FromImage(image);

try {
//生成随机生成器
Random random = new Random();

//清空图片背景色
Color color = Color.FromArgb(171, 156, 137);
g.Clear(color);

//画图片的背景噪音线
for (int i = 0; i < 1; i++) {
int x1 = random.Next(image.Width);
int x2 = random.Next(image.Width);
int y1 = random.Next(image.Height);
int y2 = random.Next(image.Height);

g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
}
//控制图片上字体
Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
//System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Black, Color.Black, 1.2f, true);
g.DrawString(checkCode, font, brush, 2, 2);

//画图片的前景噪音点
for (int i = 0; i < 1; i++) {
int x = random.Next(image.Width);
int y = random.Next(image.Height);

image.SetPixel(x, y, Color.FromArgb(random.Next()));
}

//画图片的边框线
//g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
response.ClearContent();
response.ContentType = "image/Gif";
response.BinaryWrite(ms.ToArray());
} finally {
g.Dispose();
image.Dispose();
}

return checkCode;
}

/// <summary>
/// 生成随机数
/// </summary>
/// <returns></returns>
private static string GenerateCheckCode()
{
int number;
char code;
string checkCode = String.Empty;

System.Random random = new Random();

for (int i = 0; i < 4; i++) {
number = random.Next();

if (number % 2 == 0)
code = (char)('0' + (char)(number % 10));
else
code = (char)('A' + (char)(number % 26));

checkCode += code.ToString();
}
return checkCode;
}