/// <summary>/// 生成内存位图/// </summary>/// <param name="Code"></param>/// <returns></returns>public static Bitmap GetCode(out string Code){    int imgWidth = 80;    int imgHeight = 40;    //获取随机字符    Code = DateTimeHelper.GetCode_Ran(4);    //颜色列表，用于验证码、噪线、噪点     Color[] color = { Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue };    //字体列表，用于验证码     string[] font = { "Times New Roman", "MS Mincho", "Book Antiqua", "Gungsuh", "PMingLiU", "Impact" };    Bitmap bmp = new Bitmap(imgWidth, imgHeight);    Graphics g = Graphics.FromImage(bmp);    g.Clear(Color.White);    Random rnd = new Random();    //画噪线     for (int i = 0; i < 10; i++)    {        int x1 = rnd.Next(imgWidth);        int y1 = rnd.Next(imgHeight);        int x2 = rnd.Next(imgWidth);        int y2 = rnd.Next(imgHeight);        Color clr = color[rnd.Next(color.Length)];        g.DrawLine(new Pen(clr), x1, y1, x2, y2);    }    //画验证码字符串     for (int i = 0; i < Code.Length; i++)    {        string fnt = font[rnd.Next(font.Length)];        Font ft = new Font(fnt, 18);        Color clr = color[rnd.Next(color.Length)];        g.DrawString(Code[i].ToString(), ft, new SolidBrush(clr), (float)i * 19, (float)8);    }    //画噪点     for (int i = 0; i < 100; i++)    {        int x = rnd.Next(bmp.Width);        int y = rnd.Next(bmp.Height);        Color clr = color[rnd.Next(color.Length)];        bmp.SetPixel(x, y, clr);    }    //显式释放资源     // bmp.Dispose();    g.Dispose();    return bmp;}/// <summary>/// 生成位图，输出到响应流/// </summary>/// <param name="Response"></param>/// <param name="Code"></param>public static void GetCode(HttpResponseBase Response, out string Code){    Code = string.Empty;    Bitmap bit = GetCode(out Code);    ////清除该页输出缓存，设置该页无缓存     //Response.Buffer = true;    //Response.ExpiresAbsolute = DateTime.Now.AddMilliseconds(0);    //Response.Expires = 0;    //Response.CacheControl = "no-cache";    //Response.AppendHeader("Pragma", "No-Cache");    Response.ClearContent();    bit.Save(Response.OutputStream, ImageFormat.Png);    Response.ContentType = "image/png";    //释放资源    bit.Dispose();}