Asp.net uses ashx to generate a graphical verification code, asp. netashx

Asp.net uses ashx to generate a graphical verification code, asp. netashx

This example describes how asp.net uses ashx to generate a graphic verification code. We will share this with you for your reference. The details are as follows:

You can understand the benefits of verification codes. On the Internet, I saw someone Directly Writing the verification code on the aspx page. That is to say, this method is not scientific to request a verification code. As shown below

<form id="form1" runat="server">  <div>    <asp:Image ID="Image1" runat="server" ImageUrl="Default.aspx" />    <br />    <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>    <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />  </div></form>

This Code seems to be a waste of code writing, and it is really depressing to write the code. Do not write a script for the next switch.

The following describes how to implement this function.

1. Write an ashx to generate a graphic verification code.

Using System; using System. collections; using System. data; using System. linq; using System. web; using System. web. services; using System. web. services. protocols; using System. xml. linq; using System. web. sessionState; using System. drawing; namespace usechecknum. ashx {// <summary> /// $ Brief description of codebehindclassname $ /// </summary> [WebService (Namespace =" http://tempuri.org/ ")] [WebServiceBinding (ConformsTo = WsiProfiles. basicProfile1_1)] public class doCreateNum: IHttpHandler, IRequiresSessionState {public void ProcessRequest (HttpContext context) {context. response. contentType = "text/html"; string checkCode = GetValidation (5); // generates five random Verification Code characters: context. session ["Code"] = checkCode; // Save the string to the Session so that System can be verified as needed. drawing. bitmap image = new System. drawing. bitmap (70, 22); Graphics g = Graphics. fromImage (image); try {// generate Random generator random Random = new Random (); // clear the image background color g. clear (Color. white); // specifies the background noise line of the image. int I; for (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. 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); // The foreground noise of the picture. g. 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 () ;}} public string GetValidation (int num) {string str = "0123456789 ABCDEFGHIJKLMNOPQRSTUVWXYZ"; // "or" string validatecode = ""; random rd = new Random (); for (int I = 0; I <num; I ++) {validatecode + = str. substring (rd. next (0, str. length), 1) ;}return validatecode;} public bool IsReusable {get {return false ;}}}}

2. The verification code is displayed on the page. Because the image is generated, you can directly write the verification code in the label. You only need to write a simple script and then click the mouse to switch the verification code.

<% @ Page Language = "C #" AutoEventWireup = "true" CodeBehind = "index. aspx. cs" Inherits = "usechecknum. _ Default" %> <! DOCTYPE html PUBLIC "-// W3C // dtd xhtml 1.0 Transitional // EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
After talking for half a day, it's time to see what the generated verification code looks like.