C#验证码

code：

using System;
using System.IO;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;

namespace HyeyClass.Common
{
	/// <summary>
	/// ClassName:DrawValidateImg
	/// Auther:Hyey.wl
	/// Time:2010-04-30
	/// Other:
	/// DrawValidateImg 的摘要说明。
	/// </summary>
	public class DrawValidateImg
	{
		/// <summary>
		/// 无参构造
		/// Initializes a new instance of the <see cref="DrawValidateImg"/> class.
		/// </summary>
		public DrawValidateImg()
		{
			//
			// TODO: 在此处添加构造函数逻辑
			//
		}

        
		/// <summary>
		/// 带有生成字符个数的构造
		/// Initializes a new instance of the <see cref="DrawValidateImg"/> class.
		/// </summary>
		/// <param name="charNum">The char num.验证码中包含随机字符的个数</param>
		public DrawValidateImg(int charNum)
		{
			this.CharNum = charNum;
		}


		/// <summary>
		/// 带有验证码图片宽度和高度的构造
		/// Initializes a new instance of the <see cref="DrawValidateImg"/> class.
		/// </summary>
		/// <param name="width">The width.验证码图片宽度</param>
		/// <param name="height">The height.验证码图片高度</param>
		public DrawValidateImg(int width ,int height)
		{
			this.width = width;
			this.height = height;
		}


		/// <summary>
		/// 带有生成字符个数，验证码图片宽度和高度的构造
		/// Initializes a new instance of the <see cref="DrawValidateImg"/> class.
		/// </summary>
		/// <param name="charNum">The char num.验证码中包含随机字符的个数</param>
		/// <param name="width">The width.验证码图片宽度</param>
		/// <param name="height">The height.验证码图片高度</param>
		public DrawValidateImg(int charNum ,int width ,int height)
		{
			this.CharNum = charNum;
			this.width = width;
			this.height = height;
		}


		/// <summary>
		/// 验证码中字符个数
		/// </summary>
		int charNum = 5; //默认字符个数为5

		/// <summary>
		/// 字数
		/// Gets or sets the char num.
		/// </summary>
		/// <value>The char num.</value>
		public int CharNum
		{
			get { return charNum; }
			set { charNum = value; }
		}
		/// <summary>
		/// 字号
		/// </summary>
		int fontSize =20;

		/// <summary>
		/// 字号
		/// Gets the size of the font.
		/// </summary>
		/// <value>The size of the font.</value>
		public int FontSize
		{
			get { return fontSize; }
		}
		/// <summary>
		/// 图片宽度
		/// </summary>
		int width=200;

		/// <summary>
		/// Gets the width.
		/// </summary>
		/// <value>The width.</value>
		public int Width
		{
			get { return width; }
		}

		/// <summary>
		/// 图片高度
		/// </summary>
		int height=50;

		/// <summary>
		/// Gets or sets the height.
		/// </summary>
		/// <value>The height.</value>
		public int Height
		{
			get { return height; }
			set { height = value; }
		}
                
		/// <summary>
		/// 随机生成的字符串
		/// </summary>
		string validStr="";

		/// <summary>
		/// Gets or sets the valid STR.
		/// 随机生成的字符串
		/// </summary>
		/// <value>The valid STR.</value>
		public string ValidStr
		{
			get { return validStr; }
			set { validStr = value; }
		}

		/// <summary>
		/// 产生指定个数的随机字符串，默认字符个数为5
		/// </summary>
		void GetValidateCode()
		{
			Random rd = new Random(); //创建随机数对象            

			//产生由 charNum 个字母或数字组成的一个字符串
			string str = "ABCDEFGHJKLMNPQRSTUVWYZ23456789";//共31个字符，除 l,o,x,I,O,X,1,0 的所有数字和大写字母
           
			for (int i = 0; i < charNum; i++)
			{
				validStr = validStr + str[rd.Next(30)];//返回0到54
			}			
                        
		}
                
		/// <summary>
		/// 由随机字符串，随即颜色背景，和随机线条产生的Image
		/// 返回 MemoryStream
		/// </summary>
		/// <returns>MemoryStream</returns>
		public MemoryStream GetImgWithValidateCode()
		{
			//产生随机字符串
			GetValidateCode();

			//声明一个位图对象
			Bitmap bitMap = null;
			//声明一个绘图画面
			Graphics gph = null;
			//创建内存流
			using(MemoryStream memStream = new MemoryStream())
			{
                        
				Random random = new Random();
                        
				//由给定的需要生成字符串中字符个数 CharNum， 图片宽度 Width 和高度 Height 确定字号 FontSize，
				//确保不因字号过大而不能全部显示在图片上
				int fontWidth=(int)Math.Round(width/(charNum+2)/1.3);
				int fontHeight=(int)Math.Round(height/1.5);
				//字号取二者中小者，以确保所有字符能够显示，并且字符的下半部分也能显示
				fontSize = fontWidth <= fontHeight ? fontWidth : fontHeight;

				//创建位图对象
				bitMap = new Bitmap(width+FontSize,height);
                
				//根据上面创建的位图对象创建绘图图面
				gph = Graphics.FromImage(bitMap);

				//设定验证码图片背景色
				gph.Clear(GetControllableColor(200));
				//gph.Clear(Color.White);
				
				//产生随机干扰线条
//				for (int i = 0; i < 10; i++)
//				{
//					Pen backPen = new Pen(GetControllableColor(100), 2);
//					//线条起点
//					int x = random.Next(width);
//					int y = random.Next(height);
//					//线条终点
//					int x2 = random.Next(width);
//					int y2 = random.Next(height);
//					//划线
//					gph.DrawLine(backPen, x, y, x2, y2);
//				}

				//定义一个含10种字体的数组
				String[] fontFamily ={ "Arial", "Verdana", "Comic Sans MS", "Impact", "Haettenschweiler", 
										 "Lucida Sans Unicode", "Garamond", "Courier New", "Book Antiqua", "Arial Narrow" };
//				SolidBrush sb = new SolidBrush(GetControllableColor(0));
				
				PointF Cpoint1=new PointF(5,5);   
				Random rnd1 = new Random(); 
				int x1 = 0, y1 = 0;
				//通过循环,绘制每个字符,
				for (int i = 0; i < validStr.Length; i++)
				{
					//随机字符位置   
                    x1 = rnd1.Next(10)+40*i;
					y1 = rnd1.Next(bitMap.Height/4);
					Cpoint1 = new PointF(x1,y1);
                    
					//随机字符颜色,应根据背景作适当调整以免显示模糊不清
					SolidBrush sb = new SolidBrush(Color.FromArgb(rnd1.Next(100), rnd1.Next(100), rnd1.Next(100)));  
					

					//Font textFont = new Font(fontFamily[random.Next(10)], fontSize, FontStyle.Bold);//字体随机,字号大小30,加粗 
					Font textFont = new Font("Arial",35 , FontStyle.Bold);//字体随机,字号大小30,加粗 
                     
					//随机倾斜字符  
					gph.TranslateTransform(10, 0);
					Matrix transform = gph.Transform;   
                    transform.Shear(Convert.ToSingle( rnd1.NextDouble()-0.5),0.001f);  
					gph.Transform = transform; 
					//每次循环绘制一个字符,设置字体格式,画笔颜色,字符相对画布的X坐标,字符相对画布的Y坐标
					//int space = (int)Math.Round((double)((width - fontSize * (CharNum + 2)) / CharNum));
					//纵坐标
					int y = (int)Math.Round((double)((height - fontSize)/3));
//					gph.DrawString(validStr.Substring(i, 1), textFont, sb, fontSize + i * (fontSize + space), y);
					gph.DrawString(validStr.Substring(i, 1), textFont, sb, Cpoint1);
					gph.ResetTransform(); 
				}
				//扭曲图片
				//bitMap=TwistImage(bitMap, true, random.Next(3,5),random.Next(3));
                
				
				//画图片的前景噪音点
//				for (int i = 0; i < 10; i++)
//				{
//					int x = random.Next(bitMap.Width);
//					int y = random.Next(bitMap.Height);
//					bitMap.SetPixel(x, y, Color.White);
//				}

				//画图片的边框线
				gph.DrawRectangle(new Pen(Color.Black,2), 0, 0, bitMap.Width - 1, bitMap.Height - 1);


				try
				{
                                
					bitMap.Save(memStream, ImageFormat.Gif);
                             
				}
				catch (Exception ex)
				{
					System.Windows.Forms.MessageBox.Show(ex.Message);
				}
				
				bitMap.Dispose();

//				Image img = Image.FromStream(memStream);
//				gph.DrawImage(img, 50, 20, width, 10);
                
				//gph.Dispose();
				//return img;
				return  memStream;
			}
		}
		/// <summary>
		/// 产生一种 R,G,B 均大于 colorBase 随机颜色，以确保颜色不会过深
		/// </summary>
		/// <param name="colorBase">The color base.</param>
		/// <returns>背景色</returns>
		Color GetControllableColor(int colorBase) 
		{
			Color color=Color.Black;
			if (colorBase > 200) 
			{
				System.Windows.Forms.MessageBox.Show("可控制颜色参数大于200，颜色默认位黑色");
			}
			Random random = new Random();
			//确保 R,G,B 均大于 colorBase，这样才能保证背景色较浅
			color= Color.FromArgb(random.Next(56) + colorBase, random.Next(56) + colorBase, random.Next(56) + colorBase);
			return color;
		}

		/// <summary>
		/// 扭曲图片
		/// </summary>
		/// <param name="srcBmp">The SRC BMP.</param>
		/// <param name="bXDir">if set to <c>true</c> [b X dir].</param>
		/// <param name="dMultValue">The d mult value.</param>
		/// <param name="dPhase">The d phase.</param>
		/// <returns></returns>
		Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
		{
			int leftMargin = 0;
			int rightMargin = 0;
			int topMargin = 0;
			int bottomMargin = 0;
			//float PI = 3.14159265358979f;
			float PI2 = 6.28318530717959f;
			Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);
			double dBaseAxisLen = bXDir ? Convert.ToDouble(destBmp.Height) : Convert.ToDouble(destBmp.Width);
			for (int i = 0; i < destBmp.Width; i++)
			{
				for (int j = 0; j < destBmp.Height; j++)
				{
					double dx = 0;
					dx = bXDir ? PI2 * Convert.ToDouble(j) / dBaseAxisLen : PI2 * Convert.ToDouble(i) / dBaseAxisLen;
					dx += dPhase;
					double dy = Math.Sin(dx);

					//取得当前点的颜色        
					int nOldX = 0;
					int nOldY = 0;
					nOldX = bXDir ? i + Convert.ToInt32(dy * dMultValue) : i;
					nOldY = bXDir ? j : j + Convert.ToInt32(dy * dMultValue);
					System.Drawing.Color color = srcBmp.GetPixel(i, j);
					if (nOldX >= leftMargin && nOldX < destBmp.Width - rightMargin && nOldY >= bottomMargin && nOldY < destBmp.Height - topMargin)
					{
						destBmp.SetPixel(nOldX, nOldY, color);
					}
				}
			}
			return destBmp;
		}






		/// <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 (validStr.ToUpper().Equals(inputValCode.ToUpper()))//无论输入大小写都转换为大些判断
			{
				return true;
			}
			else 
			{
				return false;
			}
		}
	}
}