The ASP. NET code for generating verification codes introduced in this article comes from the eping blog. It is quite simple and the content details are clearly stated. The implementation method is as follows:
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; // Add reference Public partial class _ default: system. Web. UI. Page
{
Protected void page_load (Object sender, eventargs E)
{
// Call a custom method to draw a verification code
Createcheckcodeimage (generatecheckcode ());
} Private string generatecheckcode ()
{
// Create an integer variable
Int number;
// Create a variable
Char code;
// Create a string variable and initialize it as null
String checkcode = string. empty;
// Create a random object
Random random = new random ();
// Use the for loop to generate four numbers
For (INT I = 0; I <4; I ++)
{
// Generate a random number
Number = random. Next ();
// Convert the number to the numeric type
Code = (char) ('0' + (char) (Number % 10 )); Checkcode + = code. tostring ();
}
// Add the generated random number to cookies
Response. Cookies. Add (New httpcookie ("checkcode", checkcode ));
// Return a string
Return checkcode;
} Private void createcheckcodeimage (string checkcode)
{
// Judge whether the string is not equal to null or null
If (checkcode = NULL | checkcode. Trim () = string. Empty)
Return;
// Create a bitmap object
System. Drawing. bitmap image = new system. Drawing. Bitmap (INT) math. Ceiling (checkcode. length * 12.5), 22 );
// Create a graphics object
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 ); // Draw the background noise line of the image
For (INT I = 0; I <2; 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. Black), X1, Y1, X2, Y2 );
} Font font = new system. Drawing. Font ("Arial", 12, (system. Drawing. fontstyle. Bold ));
System. drawing. drawing2d. lineargradientbrush brush = new system. drawing. drawing2d. lineargradientbrush (New rectangle (0, 0, image. width, image. height), color. blue, color. darkred, 1.2f, true );
G. drawstring (checkcode, Font, brush, 2, 2 ); // Foreground noise of the image
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 ); // Output the image to the page
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 ());
}
Finally
{
G. Dispose ();
Image. Dispose ();
}
}
}
Style = "cursor: hand; width: 76px; Height: 21px" onclick = "This. src = This. SRC + '? '"/> |
