Example of the code generation function implemented by ASP. NET [demo source code], asp. netdemo

Example of the code generation function implemented by ASP. NET [demo source code], asp. netdemo

This example describes the function of generating verification codes implemented by ASP. NET. We will share this with you for your reference. The details are as follows:

Verification Code Generation Principle: generate a random character, generate the character into an image, and store it in the Session. Then, verify that the content entered by the user matches the verification code in the Session.

: You can click to switch the verification code information.

General handler: CheckCodeHandler. cs

<% @ WebHandler Language = "C #" Class = "CheckCodeHandler" %> using System; using System. web; using System. text; using System. drawing; using System. web. sessionState; public class CheckCodeHandler: IHttpHandler, IRequiresSessionState {// character set that generates the verification code public string charcode = "2, 3, 4, 5, 6, 8, 9, A, B, C, D, E, f, G, H, J, K, M, N, P, R, S, U, W, X, Y, a, B, c, d, e, f, g, h, j, k, m, n, p, r, s, u, w, x, y "; public void ProcessRequest (HttpContext context) {String validateCode = CreateRandomCode (4); context. session ["ValidateCode"] = validateCode; // Save the verification code to CreateCodeImage (validateCode, context);} public bool IsReusable {get {return false ;}} /// <summary> /// generate the verification code /// </summary> /// <param name = "n"> Number of verification codes </param> /// <returns> Verification code string </returns> public string CreateRandomCode (int n) {string [] CharArray = charcode. split (','); // converts a string to a character array String randomCode = ""; int temp =-1; Random rand = new Random (); for (int I = 0; I <n; I ++) {if (temp! =-1) {rand = new Random (I * temp * (int) DateTime. now. ticks);} int t = rand. next (CharArray. length-1); if (temp! =-1 & temp = t) {return CreateRandomCode (n);} temp = t; randomCode + = CharArray [t];} return randomCode ;} public void CreateCodeImage (string checkCode, HttpContext context) {int iwidth = (int) (checkCode. length * 13); System. drawing. bitmap image = new System. drawing. bitmap (iwidth, 20); Graphics g = Graphics. fromImage (image); Font f = new System. drawing. font ("Arial", 12, (System. drawing. fontStyle. italic | System. drawing. fontStyle. bold); // foreground color: Brush B = new System. drawing. solidBrush (Color. black); // background color g. clear (Color. white); // fill in the Text g. drawString (checkCode, f, B, 0, 1); // random line Pen linePen = new Pen (Color. gray, 0); Random rand = new Random (); for (int I = 0; I <5; I ++) {int x1 = rand. next (image. width); int y1 = rand. next (image. height); int x2 = rand. next (image. width); int y2 = rand. next (image. height); g. drawLine (linePen, x1, y1, x2, y2);} // random point for (int I = 0; I <30; I ++) {int x = rand. next (image. width); int y = rand. next (image. height); image. setPixel (x, y, Color. gray);} // border g. drawRectangle (new Pen (Color. gray), 0, 0, image. width-1, image. height-1); // output image System. IO. memoryStream MS = new System. IO. memoryStream (); image. save (MS, System. drawing. imaging. imageFormat. jpeg); context. response. clearContent (); context. response. contentType = "image/jpeg"; context. response. binaryWrite (ms. toArray (); g. dispose (); image. dispose ();}}

Encapsulated as a Class Library: ValidateNumber. cs

Using System; using System. collections. generic; using System. linq; using System. web; using System. drawing; using System. web. UI; using System. drawing. drawing2D; using System. IO; using System. drawing. imaging; /// <summary> /// ValidateNumber: generate the verification code. /// </summary> public class ValidateNumber {// character set that generates the verification code (confusing characters are removed) private string charcode = "2, 3, 4, 5, 6, 8, 9, A, B, C, D, E, F, G, H, J, K, M, N, P, r, S, U, W, X, Y, a, B, c, d, e, f, g, h, j, k, m, N, p, r, s, u, w, x, y "; /// <summary> /// Maximum length of the Verification Code /// </summary> public int MaxLength {get {return 10 ;}} /// <summary> /// minimum length of the Verification Code /// </summary> public int MinLength {get {return 1 ;}} /// <summary> /// generate the verification code /// </summary> /// <param name = "length"> specify the verification code length </param> /// <returns> </returns> public string CreateValidateNumber (int length) {string [] CharArray = charcode. split (','); // converts a string to the character array st Ring randomCode = ""; int temp =-1; Random rand = new Random (); for (int I = 0; I <length; I ++) {if (temp! =-1) {rand = new Random (I * temp * (int) DateTime. now. ticks);} int t = rand. next (CharArray. length-1); if (temp! =-1 & temp = t) {return CreateValidateNumber (length);} temp = t; randomCode + = CharArray [t];} return randomCode ;} /// <summary> /// the image for creating the verification code /// </summary> /// <param name = "context"> context object </param> /// <param name = "validateNum"> Verification Code </param> public void CreateValidateGraphic (HttpContext context, string validateNum) {int iwidth = (int) (validateNum. length * 14); Bitmap image = new Bitmap (iwidth, 22); Graphics g = Graphics. fromImage (image); try {// generate Random generator random Random = new Random (); // clear the image background color g. clear (Color. white); // The interference line of the picture. 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 Font ("Arial", 12, (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 (validateNum, font, brush, 3, 2); // foreground disturbance 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); // Save the image data. MemoryStream = new MemoryStream (); image. save (stream, ImageFormat. jpeg); // output the image context. response. clear (); context. response. contentType = "image/jpeg"; context. response. binaryWrite (stream. toArray ();} finally {g. dispose (); image. dispose ();}} /// <summary> /// obtain the length of the Verification Code image /// </summary> /// <param name = "validateNumLength"> Verification code length </param>/ // <returns> </returns> public static int GetImageWidth (int validateNumLength) {return (int) (validateNumLength * 14 );} /// <summary> /// obtain the height of the Verification Code image /// </summary> /// <returns> </returns> public static double GetImageHeight () {return 22 ;}}

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