C#教程之c#生成验证码

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C#教程之c#生成验证码

/// <summary> /// 生成随机的字符串 /// </summary> /// <param name="codeCount">验证码长度</param> /// <returns></returns> public string CreateRandomCode(int codeCount) { string allChar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,a,b,c,d,e,f,g,h,i,g,k,l,m,n,o,p,q,r,F,G,H,I,G,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,s,t,u,v,w,x,y,z"; string[] allCharArray = allChar.Split(','); string randomCode = ""; int temp = -1; Random rand = new Random(); for (int i = 0; i < codeCount; i++) { if (temp != -1) { rand = new Random(i * temp * ((int)DateTime.Now.Ticks)); } int t = rand.Next(35); if (temp == t) { return CreateRandomCode(codeCount); } temp = t; randomCode += allCharArray[t]; } return randomCode; } /// <summary> /// 创建验证码图片 /// </summary> /// <param name="validateCode"></param> /// <returns></returns> public void CreateValidateGraphic(string validateCode, HttpContext context) { Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 16.0), 27); Graphics g = Graphics.FromImage(image); try { //生成随机生成器 Random random = new Random(); //清空图片背景色 g.Clear(Color.White); //画图片的干扰线 for (int i = 0; i < 25; 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, x2, y1, y2); } Font font = new Font("Arial", 13, (FontStyle.Bold | FontStyle.Italic)); LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true); g.DrawString(validateCode, font, brush, 3, 2); //画图片的前景干扰线 for (int i = 0; i < 100; 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); //保存图片数据 image.Save(context.Response.OutputStream, ImageFormat.Jpeg); } finally { g.Dispose(); image.Dispose(); } }

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