This function is essential for websites. I found it online and used some other people's code to get my project. A general functional module.
If you need this function, you can directly copy the following code.
Front-end UI
<% @ Page Language = "C #" autoeventwireup = "true" codefile = "validatecode. aspx. cs" inherits = "ui_validatecode" %>
<! 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">
<Head runat = "server">
<Meta http-equiv = "Content-Type" content = "text/html; charset = UTF-8"/>
<Title> Verification code implementation-by wangtao </title>
<SCRIPT type = "text/JavaScript" src = "../MISC/JS/CORE/jquery. js"> </SCRIPT>
</Head>
<Body>
<SCRIPT type = "text/JavaScript">
// Click the image to change the verification code
$ (Function (){
$ ("# Validatecode"). Click (function (){
VaR src = $ (this). ATTR ("src ");
SRC + = "? "+ Math. Random ();
$ (This). ATTR ("src", Src );
})
})
</SCRIPT>
<Form ID = "validatecodeform" runat = "server">
<Div>
<Input type = "text" id = "txtcode"/>
<P> <input type = "Submit" value = "verify"/> </P>
</Div>
</Form>
</Body>
</Html>
Background code: <% @ webhandler Language = "C #" class = "getvalidatecode" %> using system; using system. web; using system. drawing; public class getvalidatecode: ihttphandler {public void processrequest (httpcontext context) {// context. response. addheader = ""; context. response. cache. setcacheability (httpcacheability. nocache); context. response. clearcontent (); context. response. contenttype = "image/GIF"; // context. response. contenttype = "image/GIF"; 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 <4; 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 the cookie. // context. session ["checkcode"] = checkcode; // context. session 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); try {// generate random generator random = new random (); // clear the image 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 to be painted 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 {G. dispose (); image. dispose ();}}}Start building with 50+ products and up to 12 months usage for Elastic Compute Service
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