Generation of C # verification code

Html

<ul>   <Li>Verification Code:</Li>   <Li>    <imgsrc= "/login/getvalidatecode?id=1"ID= "Imgcode"alt= "click Refresh"onclick= "Clickchangecode ()"  />    <ahref= "javascript:void (0)"onclick= "Clickchangecode (); return false;">Can't see clearly</a>   </Li></ul>

Js

<script type= "Text/javascript" >    function  clickchangecode () {        var code = $ ("#imgCode"). attr ("src");        $ ("#imgCode"). attr ("src", Code + "1");    } </script>

C#

 Public classvalidatecode{ Public intMaxLength {Get{return Ten; } }     Public intMinLength {Get{return 1; } }    //Generate verification Code     Public stringCreatevalidatecode (intlength) {        int[] Randmembers =New int[length]; int[] Validatenums =New int[length]; stringValidatenumberstr =""; //generate a starting sequence value        intSeekseek =unchecked((int) DateTime.Now.Ticks); Random Seekrand=NewRandom (Seekseek); intBeginseek = (int) Seekrand.next (0, int32.maxvalue-length*10000); int[] seeks =New int[length];  for(inti =0; i < length; i++) {Beginseek+=10000; Seeks[i]=Beginseek; }        //Generate random numbers         for(inti =0; i < length; i++) {Random rand=NewRandom (Seeks[i]); intPownum =1*(int) Math.pow (Ten, length); Randmembers[i]=Rand.        Next (Pownum, Int32.MaxValue); }        //extracting random numbers         for(inti =0; i < length; i++)        {            stringNumstr =Randmembers[i].            ToString (); intNumlength =numstr.length; Random Rand=NewRandom (); intNumposition = Rand. Next (0, Numlength-1); Validatenums[i]= Int32.Parse (numstr.substring (Numposition,1)); }        //Generate verification Code         for(inti =0; i < length; i++) {Validatenumberstr+=Validatenums[i].        ToString (); }        returnValidatenumberstr; }    //generate a picture of the captcha     Public byte[] Createvalidategraphic (stringValidatecode) {Bitmap image=NewBitmap ((int) Math.ceiling (validatecode.length*12.0), A); Graphics g=graphics.fromimage (image); Try        {            //Generate random GeneratorsRandom random =NewRandom (); //clear the background color of the pictureg.clear (Color.White); //interference lines for drawing pictures             for(inti =0; I < -; i++)            {                intX1 =Random. Next (image.                Width); intx2 =Random. Next (image.                Width); intY1 =Random. Next (image.                Height); inty2 =Random. Next (image.                Height); G.drawline (NewPen (color.silver), x1, y1, x2, y2); } Font Font=NewFont ("Arial", A, (FontStyle.Bold |fontstyle.italic)); LinearGradientBrush Brush=NewLinearGradientBrush (NewRectangle (0,0, image. Width, image. Height),
Color.Blue, Color.darkred,1.2f,true); g.DrawString (Validatecode, font, brush,3,2); //foreground interference point of picture painting             for(inti =0; I < -; i++)            {                intx =Random. Next (image.                Width); inty =Random. Next (image.                Height); Image. SetPixel (x, Y, Color.FromArgb (random.            Next ())); }            //draw the border line of a pictureG.drawrectangle (NewPen (Color.silver),0,0, image. Width-1, image. Height-1); //Save picture DataMemoryStream stream =NewMemoryStream (); Image.            Save (stream, imageformat.jpeg); //Output Picture Stream            returnStream.        ToArray (); }        finally{g.dispose (); Image.        Dispose (); }    }    //get the length of the Verification code picture     Public Static intGetimagewidth (intvalidatenumlength) {        return(int) (validatenumlength*12.0); }    //get the height of the verification code     Public Static Doublegetimageheight () {return 22.5; }}

Call

 PublicActionResult Checkcode () {//class that instantiates the CAPTCHA firstValidatecode Validatecode =NewValidatecode (); //generates the length specified by the Verification code    stringCode = Validatecode.createvalidatecode (5); //Assigning a verification code to a session variablesession["Validatecode"] =Code; //Create a picture of the verification code    byte[] bytes =validatecode.createvalidategraphic (code); //Finally, the verification code is returned    returnFile (Bytes,@"Image/jpeg");}

Generation of C # verification code