public partial class ValidatImg : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { string str = "0123456789"; char[] chs = str.ToCharArray(); Random rand = new Random(); string validater = ""; for (int i = 0; i < 4; i++) { char x = chs[rand.Next(0, chs.Length)]; validater += x; } Session["xk_Validate_code"] = validater; CreateImage(validater); } protected void CreateImage(string str) { int iWidth = str.Length * 11; Bitmap img = new Bitmap(iWidth, 20); Graphics g = Graphics.FromImage(img); g.Clear(Color.White); Color[] colors = new Color[] { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Chocolate, Color.Brown, Color.DarkCyan, Color.Purple }; Random rand = new Random(); for (int i = 0; i < str.Length; i++) { Color c = colors[rand.Next(0, colors.Length)]; Font f = new Font("Courier New", 11); Brush b = new System.Drawing.SolidBrush(c); //画字符 g.DrawString(str.Substring(i, 1), f, b, (i * 10) + 1, 1, StringFormat.GenericDefault); } //描边 g.DrawRectangle(new Pen(Color.Black), 0, 0, img.Width - 1, img.Height - 1); //保存图像到内存 MemoryStream ms = new MemoryStream(); img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); Response.Clear(); Response.ContentType = "image/Jpeg"; Response.BinaryWrite(ms.ToArray()); g.Dispose(); img.Dispose(); } }