sqlconnection problem

Question

I have created a database file userData.mdf. And have a created a class named dbHelper. Here i have made three functions:

                                    OpenConnection();

                                    ExecuteQry();

                                      CloseConnection();

 

The problem is here:

using System;

using System.Collections.Generic;

using System.Data.SqlClient;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace Insert_Delete_UpdateOperation

{

public class dbhelper

{

public static SqlConnection sqlConnection;

public static SqlDataReader sqlDataReader;

public static void OpenConnection()

{

String connectionString = "Data Source=(LocalDB)\v11.0;AttachDbFilename="c:\users\suraj\documents\visual studio 2012\Assignment\Insert,Delete,UpdateOperation\Insert,Delete,UpdateOperation\userData.mdf"; Integrated Security=True";);

sqlConnection = new SqlConnection(connectionString);

sqlConnection.Open();

}

public static void ExecuteQry(string qry,Boolean state)

{

SqlCommand sqlcommand=new SqlCommand(qry,sqlConnection);

if(state)

{

sqlcommand.ExecuteNonQuery();

}

else

{

sqlDataReader=sqlcommand.ExecuteReader();

}

}

public static void CloseConnection()

{

if(sqlConnection.State==System.Data.ConnectionState.Open)

{

sqlConnection.Close();

}

}

}

}