Code to generate an English character digital verification code under ASP.

Using System; Using System.Data; Using System.Configuration; Using System.Web; Using System.Web.Security; Using System.Web.UI; Using System.Web.UI.WebControls; Using System.Web.UI.WebControls.WebParts; Using System.Web.UI.HtmlControls; Using System.Drawing; Using System.Drawing.Drawing2D; Public partial class _default:system.web.ui.page {protected void Page_Load (object sender, EventArgs e) {Bitmap BMP = N EW Bitmap (50, 25); Graphics g = graphics.fromimage (BMP); SolidBrush sb = new SolidBrush (GetColor ()); g.DrawString (CheckNumber (), New Font ("Arial", +), SB, 0, 0); Bmp. Save (Response.outputstream, System.Drawing.Imaging.ImageFormat.Gif); } public static string CheckNumber () {String checkcode = " ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ "; int len = 4; String tmpstr = ""; int irandnum; Random rnd = new Random (); for (int i = 0; i < len; i++) {irandnum = rnd. Next (Checkcode. Length); Tmpstr + = Checkcode[irandnum]; } return TMPSTR; } private Color GetColor () {Random R = new Random (); Return Color.FromArgb (R.next, R.next (n), R.next (256)); } }