Asp.net verification code generation class

Using System;
Using System. Drawing;
Using System. Drawing. Imaging;
Using System. Web. UI;
Using System. Drawing. Drawing2D;
Using System. IO;
Namespace Validate
{
/// <Summary>
/// The class that generates the verification code
/// </Summary>
Public class ValidateNumber
{
Public ValidateNumber ()
{
}
/// <Summary>
/// Maximum length of the Verification Code
/// </Summary>
Public int MaxLength
{
Get {return 10 ;}
}
/// <Summary>
/// Minimum length of the Verification Code
/// </Summary>
Public int MinLength
{
Get {return 1 ;}
}
/// <Summary>
/// Generate the verification code
/// </Summary>
/// <Param name = "length"> specify the length of the Verification Code </param>
/// <Returns> </returns>
Public string CreateValidateNumber (int length)
{
Int [] randMembers = new int [length];
Int [] validateNums = new int [length];
String validateNumberStr = "";
// Generate the starting Sequence Value
Int seekSeek = unchecked (int) DateTime. Now. Ticks );
Random seekRand = new Random (seekSeek );
Int beginSeek = (int) seekRand. Next (0, Int32.MaxValue-length * 10000 );
Int [] seeks = new int [length];
For (int I = 0; I <length; I ++)
{
BeginSeek ++ = 10000;
Seeks [I] = beginSeek;
}
// Generate random numbers
For (int I = 0; I <length; I ++)
{
Random rand = new Random (seeks [I]);
Int pownum = 1 * (int) Math. Pow (10, length );
RandMembers [I] = rand. Next (pownum, Int32.MaxValue );
}
// Extract random numbers
For (int I = 0; I <length; I ++)
{
String numStr = randMembers [I]. ToString ();
Int numLength = numStr. Length;
Random rand = new Random ();
Int numPosition = rand. Next (0, numLength-1 );
ValidateNums [I] = Int32.Parse (numStr. Substring (numPosition, 1 ));
}
// Generate the verification code
For (int I = 0; I <length; I ++)
{
ValidateNumberStr + = validateNums [I]. ToString ();
}
Return validateNumberStr;
}
/// <Summary>
/// Image of the Verification Code
/// </Summary>
/// <Param name = "containsPage"> page object to be output </param>
/// <Param name = "validateNum"> Verification Code </param>
Public void CreateValidateGraphic (Page containsPage, string validateNum)
{
Bitmap image = new Bitmap (int) Math. Ceiling (validateNum. Length * 12.5), 22 );
Graphics g = Graphics. FromImage (image );
Try
{
// Generate a random Generator
Random random = new Random ();
// Clear the background color of the image
G. Clear (Color. White );
// Picture interference line
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
ContainsPage. Response. Clear ();
ContainsPage. Response. ContentType = "image/jpeg ";
ContainsPage. Response. BinaryWrite (stream. ToArray ());
}
Finally
{
G. Dispose ();
Image. Dispose ();
}
}
/// <Summary>
/// Obtain the length of the Verification Code Image
/// </Summary>
/// <Param name = "validateNumLength"> Verification code length </param>
/// <Returns> </returns>
Public static int GetImageWidth (int validateNumLength)
{
Return (int) (validateNumLength * 12.5 );
}
/// <Summary>
/// Obtain the height of the Verification Code
/// </Summary>
/// <Returns> </returns>
Public static double GetImageHeight ()
{
Return 22.5;
}
}
}