Validatecode. ashx
<% @ Webhandler Language = "C #" class = "validatecode" %> using system; using system. data; using system. web; using system. collections; using system. web. services; using system. web. services. protocols; using system. drawing;
Public class validatecode: ihttphandler {
Public void processrequest (httpcontext context) {context. response. cache. setcacheability (httpcacheability. nocache); // pay special attention. If this parameter is not added, click Verify image 'do not see another login. this. createcheckcodeimage (generatecheckcode (context), context );}
Public bool isreusable {get {return false ;}} private string generatecheckcode (httpcontext context) {int number; char code; string checkcode = string. empty;
System. Random random = new random ();
for (INT I = 0; I <6; I ++) {number = random. Next ();
If (Number % 2 = 0) code = (char) ('0' + (char) (Number % 10 )); else if (Number % 3 = 0) code = (char) (''a' + (char) (Number % 26); else code = (char) (''a' + (char) (Number % 26); checkcode + = code. tostring () ;}
Context. response. cookies. add (New httpcookie ("checkcode", checkcode); // It can also be stored in seesion. // context. session ["checkcode"] = checkcode; return checkcode ;}
Private void createcheckcodeimage (string checkcode, httpcontext context) {If (checkcode = NULL | checkcode. Trim () = string. Empty) return;
System. drawing. bitmap image = new system. drawing. bitmap (INT) math. ceiling (checkcode. length * 12.5), 22); graphics G = graphics. fromimage (image );
& Nbs
P; try {// generate the random generator random = new random ();
// Clear the background color G. Clear (color. White );
// specifies the background noise 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 system. drawing. font ("Arial", 12, (system. drawing. fontstyle. bold | system. drawing. fontstyle. italic); 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 G of the image. 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); context. response. clearcontent (); context. response. contenttype = "image/GIF"; context. response. binarywrite (Ms. toarray ();} finally & nbs
P; {G. Dispose (); image. Dispose ();}
}}
Page:
<% @ Page Language = "C #" autoeventwireup = "true" codefile = "default. aspx. cs" inherits = "default" %>
<! Doctype HTML public "-// W3C // dtd xhtml 1.0 transitional // en" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<HTML xmlns = "http://www.w3.org/1999/xhtml">
R/> </form> </body>
BackgroundCode:
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;
Public partial class default: system. Web. UI. Page {protected void page_load (Object sender, eventargs e ){
}
protected void button#click (Object sender, eventargs e) {If (request. cookies ["checkcode"] = NULL) {lblmessage. TEXT = "your browser settings have been disabled. You must set the options that allow the browser to use cookies before using the system. "; Lblmessage. Visible = true; return ;}
If (string. Compare (request. Cookies ["checkcode"]. Value, txtcheckcode. Text, true )! = 0) {lblmessage. Text = "Incorrect verification code. Enter the correct verification code. "; Lblmessage. Visible = true; return ;}
// Execute the next step here // checkcode is saved to the session // If (session ["checkcode"]! = NULL) // {// If (string. Compare (session ["checkcode"]. tostring (), txtcheckcode. Text. Trim (), true )! = 0) // {// lblmessage. Text = "the verification code is incorrect. Enter the correct verification code. "; // Lblmessage. Visible = true; // return; //} // else // {// execute the next step here //}//}}}
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