MVC generates security Verification code (example: for login verification) (Code turn)

---------HTML

<td> captcha:</td>           <td>                              <div style= "float:right; margin-top:5px;" >                   <a href= "javascript:void (0)" onclick= "Clickremovechangecode (); return false;" > can not see Clearly, change a </a>               </div>           </td>

-----------jquery

Click Re-change the CAPTCHA function Clickremovechangecode () {    var code = $ ("#imgCode"). attr ("src");    $ ("#imgCode"). attr ("src", Code + "1");}   

------------ASP. NET MVC returns file address

<summary>///Verification Code///</summary>///<param name= "context" ></param>///<returns> </returns>public ActionResult Checkcode () {    //Generate Verification code    Validatecode Validatecode = new Validatecode ();    String code = Validatecode.createvalidatecode (4);    session["Validatecode"] = code;    byte[] bytes = validatecode.createvalidategraphic (code);    Return File (bytes, @ "Image/jpeg");}

Class----generate verification codes and draw backgrounds

public class Validatecode {public Validatecode () {}///<summary>///verification code max.        Length///</summary> public int MaxLength {get {return 10;}            }///<summary>///Minimum length of verification code///</summary> public int MinLength {        get {return 1;} }///<summary>//Generate verification codes///</summary>//<param name= "Length" > Specify the lengths of the Captcha &L            t;/param>//<returns></returns> public string createvalidatecode (int length) {            int[] randmembers = new Int[length];            int[] validatenums = new Int[length];            String validatenumberstr = "";            Generates the starting sequence value int seekseek = unchecked ((int) DateTime.Now.Ticks);            Random Seekrand = new Random (Seekseek);            int beginseek = (int) seekrand.next (0, Int32.maxvalue-length * 10000); Int[] seeks = new Int[length];                for (int i = 0; i < length; i++) {Beginseek + = 10000;            Seeks[i] = Beginseek; }//Generate random numbers for (int i = 0; i < length; i++) {Random rand = new Random (                Seeks[i]);                int pownum = 1 * (int) Math.pow (ten, length); Randmembers[i] = rand.            Next (Pownum, Int32.MaxValue); }//extract random numbers for (int i = 0; i < length; i++) {String numstr = Randmembe Rs[i].                ToString ();                int numlength = Numstr.length;                Random rand = new Random (); int numposition = rand.                Next (0, numLength-1);            Validatenums[i] = Int32.Parse (numstr.substring (numposition, 1)); }//Generate Verification code for (int i = 0; i < length; i++) {validatenumberstr + = valid Atenums[i].            ToString (); } return ValidatenumbersTr }//c# MVC Upgrade///<summary>//Create a picture of the CAPTCHA////</summary>//<param Nam E= "Containspage" > Page object to Output to </param>//<param name= "Validatenum" > Verification Code </param> public B Yte[] Createvalidategraphic (string validatecode) {Bitmap image = new Bitmap ((int) math.ceiling (Validatec Ode.            Length * 12.0), 22);            Graphics g = graphics.fromimage (image);                try {//Generate random generator randomly random = new random ();                Empty the picture background color g.clear (color.white); The interference line for the picture is (int i = 0; i <; 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 Font ("Arial", FontStyle.Bold |                Fontstyle.italic)); LinearGradientBrush brush = new LinearGradientBrush (new Rectangle (0, 0, image. Width, image.                Height), Color.Blue, color.darkred, 1.2f, true);                g.DrawString (Validatecode, Font, Brush, 3, 2); The foreground of the painting picture interferes with the point for (int i = 0; i <; 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 picture G.drawrectangle (new Pen (Color.silver), 0, 0, image. Width-1, image.                HEIGHT-1);                Save picture Data MemoryStream stream = new MemoryStream (); Image.                Save (stream, imageformat.jpeg); Output picture stream return stream.            ToArray (); } finally {G.dispoSE (); Image.            Dispose (); }}///<summary> Get the length of the CAPTCHA picture///</summary>//<param name= "Valida  Tenumlength "> Length of verification code </param>//<returns></returns> public static int getimagewidth (int        Validatenumlength) {return (int) (VALIDATENUMLENGTH * 12.0);        }//<summary>//The height of the verification code///</summary>//<returns></returns>        public static double Getimageheight () {return 22.5; }     }

　　

MVC generates security Verification code (example: for login verification) (Code turn)