. Net verification code generation class

1. First, write a verification code class.

Validatenumber

 

 

Using system;
Using system. Data;
Using system. configuration;
Using system. LINQ;
Using system. Web;
Using system. Web. Security;
Using system. Web. UI;
Using system. Web. UI. htmlcontrols;
Using system. Web. UI. webcontrols;
Using system. Web. UI. webcontrols. webparts;
Using system. xml. LINQ;
Using system. drawing;
Using system. Drawing. drawing2d;
Using system. IO;
Using system. Drawing. imaging;

/// <Summary>
/// Summary of validatenumber
/// Production verification code class
/// </Summary>
Public class validatenumber
{
Public validatenumber ()
{
 
}
// Length of the production verification code
Public int maxlength
{
Get {return 10 ;}
}
Public int minlength
{
Get {return 1 ;}
}
/// <Summary>
/// Generate the verification code
/// </Summary>
/// <Param name = "length"> specify its length </param>
/// <Returns> </returns>
Public String createvalidatenumber (INT length)
{
String validatememberstr = "";
// Declare an integer array to store random numbers
Int [] Rand = new int [length];
//////////////////////////////////////// ///// Declare an array to obtain a random number

Int [] validate = new int [length];
// The sequence value that generates a random number: time-based

Int seek = unchecked (INT) datetime. Now. ticks );
// Number of time-generated Sequences
Random seekrand = new random (seek );

// Obtain the random number of a range class
Int BS = (INT) seekrand. Next (0, int32.maxvalue-length * 10000 );

######## Redeclare an array to store random numbers
Int [] Ss = new int [length];
For (INT I = 0; I <length; I ++)
{
BS + = 10000;
Ss [I] = BS;
}
// Generate random numbers
For (INT I = 0; I <length; I ++)
{
Random rands = new random (ss [I]);
Int pownum = 1 * (INT) math. Pow (10, length );
Rand [I] = rands. Next (pownum, int32.maxvalue );
}
// Extract numbers
For (INT I = 0; I <length; I ++)
{
String numstr = Rand [I]. tostring ();
Int num = numstr. length;
Random randh = new random ();
Int numposition = randh. Next (0, num-1 );
// Give the second array
Validate [I] = int32.parse (numstr. substring (numposition, 1 ));
}
// Generate the verification code
For (INT I = 0; I <length; I ++)
{
// Generate a verification code in the random number array.
Validatememberstr + = validate [I]. tostring ();

}
Return validatememberstr;
}
// Create a verification code image and output it on the page
Public void createvalidategraphic (Page C, string validatenum)
{
Bitmap image = new Bitmap (INT) math. Ceiling (validatenum. length * 12.5), 22 );
Graphics G = graphics. fromimage (image );
// Generate the instant Generator
Random random = new random ();
// Clear the background color of the image
G. Clear (color. White );
// Draw the drying line of the image
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, Y1, X2, Y2 );

}
Font font = new font ("Arial", 12, (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 (validatenum, Font, brush, 3, 2 );
// Foreground interference points
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 ()));
}
// Draw the border line of the image
G. drawrectangle (new pen (color. Silver), 0, 0, image. Width-1, image. Height-1 );
// Save image data
Memorystream stream = new memorystream ();
Image. Save (stream, imageformat. JPEG );
// Output image
C. Response. Clear ();
C. Response. contenttype = "image/JPEG ";
C. Response. binarywrite (stream. toarray ());
}
// Verification code length
Public static int getimagewidth (INT validatenumlength)
{
Return (INT) (validatenumlength * 12.5 );
}
Public static double getimageheight ()
{
Return 22.5;
}
}
// Create a page

Write in the page

// Instantiate the Verification Code Class

Validatenumber S = new validatenumber ();

// Get a verification code number with a specified length. Create a verification code number.
String STR = S. createvalidatenumber (4 );

// Save the verification code in seesion
Session ["vnmber"] = STR;

// Create an image of the Verification Code
S. createvalidategraphic (this, STR );