C # generate a graphic Verification Code

From http://www.cnblogs.com/tuyile006/archive/2007/04/13/711874.html

Source code for generating the verification code image:

Using system;
Using system. Data;
Using system. configuration;
Using system. collections;
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. IO;

Public partial class creatimage: system. Web. UI. Page
{
Protected void page_load (Object sender, eventargs E)
{
String checkcode = createcode (4 );
Session ["checkcode"] = checkcode;
Createimage (checkcode );
}

/* Generate a Verification Code */
Public String createcode (INT codelength)
{

String so = "1, 2, 3, 4, 5, 6, 7, 8, 9, 0, A, B, C, D, E, F, G, H, I, J, K, L, M, n, O, P, Q, R, S, T, U, V, W, X, Y, Z, A, B, C, D, E, F, G, h, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z ";
String [] strarr = So. Split (',');
String code = "";
Random Rand = new random ();
For (INT I = 0; I <codelength; I ++)
{
Code + = strarr [Rand. Next (0, strarr. Length)];
}
Return code;
}

/* Generate a verification image */
Public void createimage (string code)
{

Bitmap image = new Bitmap (60, 20 );
Graphics G = graphics. fromimage (image );
Webcolorconverter WW = new webcolorconverter ();
G. Clear (color) ww. convertfromstring ("# fae264 "));

Random random = new random ();
// Draw the background noise line of the image
For (INT I = 0; I <12; 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. lightgray), X1, Y1, X2, Y2 );
}
Font font = new font ("Arial", 15, fontstyle. Bold | fontstyle. italic );
System. Drawing. drawing2d. lineargradientbrush brush = new system. Drawing. drawing2d. lineargradientbrush (
New rectangle (0, 0, image. Width, image. Height), color. Blue, color. Gray, 1.2f, true );
G. drawstring (Code, Font, brush, 0, 0 );

// Foreground noise of the image
// For (INT I = 0; I <10; I ++)
//{
// Int x = random. Next (image. width );
// Int y = random. Next (image. Height );
// Image. setpixel (X, Y, color. White );
//}

// Draw the border line of the image
// G. drawrectangle (new pen (color. Silver), 0, 0, image. Width-1, image. Height-1 );

System. Io. memorystream MS = new system. Io. memorystream ();
Image. Save (MS, system. Drawing. imaging. imageformat. GIF );
Response. clearcontent ();
Response. contenttype = "image/GIF ";
Response. binarywrite (Ms. toarray ());
G. Dispose ();
Image. Dispose ();
}
}

Usage:
Save the above Code in the webpage: createimg. aspx