Migrating legacy systems to. Net Core 2.0 Diaries (13)--Graphics verification Code

Refer to this article: http://www.cnblogs.com/yuangang/p/6000460.html

usingSystem;usingSystem.IO;usingSystem.drawingcore;usingSystem.DrawingCore.Imaging;namespacemobileweb.utility{ Public classCaptcha { Public stringCreatevalidatenumber (intlength) {            int[] Randmembers =New int[length]; int[] Validatenums =New int[length]; System.Text.StringBuilder Validatenumberstr=NewSystem.Text.StringBuilder (); //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.append (validatenums[i].            ToString ()); }            returnvalidatenumberstr.tostring (); }         Public byte[] Createvalidategraphic (stringvalidatenum) {Bitmap Img=NULL; Graphics g=NULL; MemoryStream Ms=NULL; Random Random=NewRandom (); //validation code Color collectionColor[] C ={color.black, color.red, Color.darkblue, Color.green, Color.orange, Color.brown, Color.darkcyan, Color.Purple}; //Validation code font collection            string[] fonts = {"Verdana","Microsoft Sans Serif","Comic Sans MS","Arial","Song Body" }; //defines the size of the image, creating an instance of the imageIMG =NewBitmap ((int) Validatenum.length * -, +); G= Graphics.fromimage (IMG);//generating a new Graphics object from an IMG objectg.clear (color.white);//background set to white//draw back spots at random locations             for(inti =0; I < -; i++)            {                intx =Random.                Next (Img.width); inty =Random.                Next (Img.height); G.drawrectangle (NewPen (Color.lightgray,0), X, Y,1,1); }            //verification code plotted in G             for(inti =0; i < validatenum.length; i++)            {                intCIndex = random. Next (7);//Random Color index values                intFindex = random. Next (5);//Random Font index valuesFont f =NewFont (Fonts[findex], the, FontStyle.Bold);//FontBrush B =NewSolidBrush (C[cindex]);//Color                intII =4; if((i +1) %2==0)//Control Verification code not at the same height{II=2; } g.drawstring (Validatenum.substring (i,1), F, B,3+ (I * A), ii);//draw a validation character} MS=NewMemoryStream ();//generating a memory stream objectImg.save (MS, Imageformat.jpeg);//Save this image to a stream in the format of a PNG image file//Recycling ResourcesG.dispose ();            Img.dispose (); returnMs.        ToArray (); }    }}

Call method, controller plus a method, HTML

         Public actionresult Validatecode ()        {            new  Captcha ();             var code = Captcha. Createvalidatenumber (4);            HttpContext.Session.SetString ("validatecode", code);             return " Image/jpeg " );        }

Migrating legacy systems to. Net Core 2.0 Diaries (13)--Graphics verification Code