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Validation Using Captcha Code

Posted By:Srikanth       Posted Date: April 22, 2011    Points: 40    Category: Validations    URL: http://www.dotnetspark.com  

These days many WebSites asks us to type a Captcha code for Registration purposes.There are many spams generated these days in order to stop those the best way is using CAPTCHA CODE.

This code snippet explains how to generate that random string

//Page Initiation is done here

protected void Page_Load(object sender, EventArgs e)


      displayLabel.Text=Captcha() ;     

      //(displayLabel) is the Label ID


//Defining a Method to Generate Random String

public string Captcha()


     string allowedChars  = "a,b,c,d,e,f,g,h,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,";    

     allowedChars += "A,B,C,D,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z,";    

      allowedChars += "2,3,4,5,6,7,8,9";    

      char[] sep = { ',' };    

       string[] arr = allowedChars.Split(sep);

        string passwordString = "";

    string temp;

    Random rand = new Random();

    for (int i = 0; i < 6; i++)


        temp = arr[rand.Next(0, arr.Length)];

        passwordString += temp;


    return passwordString;



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