Disable Browser Back Button using csharp

Disable Firefox and IE Back Button in Asp.net

public void ClearBrowserCache(){      HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache); 

HttpContext.Current.Response.Cache.SetExpires(DateTime.Now); HttpContext.Current.Response.Cache.SetExpires(DateTime.Now.AddSeconds(-1));

      HttpContext.Current.Response.Cache.SetNoStore();

     }

call this method in each and every page load Event.

note:This functionality will not work when you call Server.Transfer for page redirection.

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The remote certificate is invalid

The remote certificate is invalid according to the validation procedure

you will get this error because of certificates issue while getting the response from the external web service or any other Web Request from the server.

follow the below snippet to resolve this issue

using System.Net;

using System.Net.Security;

using System.Security.Cryptography.X509Certificates;

protected void Page_Load(object sender, EventArgs e)

    {

      ServicePointManager.ServerCertificateValidationCallback = RemoteCertificateValidationCB;

      Uri uri = new Uri("http://microsoft.com");

      if (uri.Scheme == Uri.UriSchemeHttp)

     {

       HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);

       request.Method = WebRequestMethods.Http.Get;

       HttpWebResponse response = (HttpWebResponse)request.GetResponse();

StreamReader reader = new StreamReader(response.GetResponseStream());     

       string tmp = reader.ReadToEnd();

Response.Write(tmp);

       response.Close();

               

     }

       

    }

public static bool RemoteCertificateValidationCB(Object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)

    {

        //If it is really important, validate the certificate issuer here.

        string resultsTrue = certificate.Issuer.ToString();

        //For now, accept any certificate

        return true;

    }

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Insert single apostrophe in sql server varchar datatype

Single Apostrophe  in Sql server

If you are using SQL strings in your database , chances are you have come across problem with strings in SQL statement. One extra apostrophe screws up the SQL string, causing the SQL statement to fail.

if you  insert the  following query it throws the error like below

insert into emp values('gurucoder's')

Error:

Msg 102, Level 15, State 1, Line 1


Incorrect syntax near 's'.

Msg 105, Level 15, State 1, Line 1
Unclosed quotation mark after the character string ')
'.


After some googled i found the solution to solve this .putting the double apostrophe in string value

insert into emp values('gurucoder''s')
 
The above query with double apostrophe will insert the values like gurucoder's in database field

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csproj is not installed error

csproj is not installed error Make sure the application for the project type (.csproj) is installed

This error occurs when u attempt to open the old visual studio project in new Version IDE...
there is no need to reset the enviroment settings and unistall the IDE .To solve this error follow the solution

solution:

Go to Run command type the below :

devenv.exe /resetskippkgs

perhaps i'm faced this error and i used the above solution it perfectly works within a minute............... 

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Fibonacci Numbers

Fibonacci Series:

Fibonacci examples:

The Fibonacci sequence is named after Leonardo of Pisa, who was known as Fibonacci (a contraction of filius Bonacci, "son of Bonaccio").
Fibonacci's 1202 book Liber Abaci introduced the sequence to Western European mathematics, although the sequence was independently
described in Indian mathematics and it is disputed which came first.



The sequence of number 1, 1, 2, 3, 5, 8, 13, 21, 34 . . . . each of which sum is the sum of the two previous numbers.
These numbers are also called Fibonacci numbers. The ratio of one Fibonacci to the preceding one is a Convergent of the
 continued fraction.The sum of the Fibonacci Sequence can be directly obtained from Pascal's triangle.Fibonacci numbers are
 named after Leonardo of Pisa, known as Fibonacci. The Fibonacci numbers are also a Lucas sequence.Fibonacci numbers can be given by,

Fn = Fn-1 + Fn-2

where, F1 = F2 = 1

F0=	0	F1=	1	F2=	1	F3=	2	F4=	3
F5=	5	F6=	8	F7=	13	F8=	21	F9=	34
F10=	55	F11=	89	F12=	144	F13=	233	F14=	377

source : wikipedia


csharp / c# program for Fibonacci series recursive example :

class Program

    {

        static void Main(string[] args)

        {

          Program p=new Program();

          

            Console.Write(p.Fib(14));

            Console.ReadLine();

        }

        public int Fib(int num)

        {

            int res;

            if (num == 1 || num == 0)

                return num;

            res = Fib(num - 1) + Fib(num - 2);

            return res;

        }

    }

Output : 377

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