Using System. Drawing;
Public partial class Pub_validcode: System. Web. UI. Page
{
Protected void Page_Load (object sender, EventArgs e)
{
This. CreateCheckCodeImage (GenerateCheckCode ());
}
// Generate a random number
Private string GenerateCheckCode ()
{
Int number;
Char code;
String checkCode = String. Empty;
System. Random random = new Random ();
For (int I = 0; I <4; I ++)
{
Number = random. Next ();
If (number % 2 = 0)
Code = (char) (0 + (char) (number % 10 ));
Else
Code = (char) (0 + (char) (number % 10 ));
// Code = (char) (a + (char) (number % 26 ));
CheckCode + = code. ToString ();
}
Response. Cookies. Add (new HttpCookie ("CheckCode", checkCode ));
// Save the generated random number to the session
Session ["Num"] = checkCode. ToString (). ToLower ();
Return checkCode;
}
Private void CreateCheckCodeImage (string checkCode)
{
If (checkCode = null | checkCode. Trim () = String. Empty)
Retu