Web Image Verification Code verification

Make a code in the Image verification code interface

1Verification Code: <asp:textbox id="TextBox1"runat="Server"></asp:textbox><asp:image id="Image1"Imageurl="yzm.aspx"runat="Server"/>2<asp:button id="Button1"runat="Server"text="Validation"/><asp:label id="Label1"runat="Server"text=""></asp:Label>3     

The image control points to yzm.aspx

<asp:image id= "Image1" imageurl= "yzm.aspx" runat= "Server"/>

Create a yzm.aspx in the background to draw the code is as follows

1 //referencing a using System.Drawing namespace2 3         //Create a canvas4Bitmap map =NewBitmap ( -, -);5         //specify to draw on that canvas6Graphics g =graphics.fromimage (map);7         //random Number class8Random r =NewRandom ();9         //Draw Background ColorTen  One         //prepare the background color and put it in the collection. AList<color> CList =NewList<color>(); - CList. ADD (color.azure); - CList. ADD (Color.lightgray); the CList. ADD (color.cornflowerblue); - CList. ADD (color.slateblue); - CList. ADD (color.mediumblue); - CList. ADD (color.steelblue); + CList. ADD (color.darkgreen); - CList. ADD (color.greenyellow); + CList. ADD (color.slateblue); A         //Draw Background Color atG.fillrectangle (NewSolidBrush (Clist[r.next (0, CList. Count)]),0,0, -, -); -           -        //Draw Interference Lines -          for(inti =0;i<Ten; i++)//Loop Draw I line of interference -         { -          //Create a Pen object pen inPen pen=NewPen (NewSolidBrush (Clist[r.next (0, CList. Count)]), R.next (0,Ten)); -         //Draw Interference Lines toG.drawline (pen, R.next (0, -), R.next (0, -), R.next (0, -), R.next (0, -)); +         } -         //Verification Code Draw content the         stringSS ="ABCDEFHIJKLMNOPQRSTUVWXYZabxdefghijklmnopqrstuvwxyz1234567890"; *         strings =""; $          for(inti =0; I <4; i++)//random four-digit verification codePanax Notoginseng         { -S + = ss. Substring ((R.next (0Ss. Length)),1); the         } +session["Yzm"] =s; A         //the font being drawn theFont f =NewFont ("blackbody", -); +         //Painted brushes -Brush B =NewSolidBrush (color.brown); $         //Start drawing Verification Code $g.DrawString (S, F, B,0,0); -  -         //Save the Drawn verification code the         //Response.outputstream output Stream -         //System.Drawing.Imaging.ImageFormat.Jpeg saved formatsWuyi map. Save (Response.outputstream, System.Drawing.Imaging.ImageFormat.Jpeg); theResponse.End ();

Page display

Validation code method

//Registration Verification button click eventButton1.Click + =button1_click;
    voidButton1_Click (Objectsender, EventArgs e) {        stringT1 =TextBox1.Text; stringT2 = session["YZM"].        ToString (); if(t1. ToUpper () = =T2. ToUpper ()) {Label1.Text="Verify Success! "; }        Else{Label1.Text="validation failed! "; }    }

See not clear click Picture Replacement verification code with JS method

<script type="text/javascript">    var0;    document.getElementById ("Image1"). onclick = function () {          this. SetAttribute ("src""yzm.aspx?id= " + a);        A+ +;    } </script>

Web Image Verification Code verification