Question

i have created a function which executes query and returns SqlDataReader, now i am using that in another function work with the returned data, but i gets the error saying reader is already closed. here is the functions:

public static SqlDataReader ExecuteReader(string procedure, SqlParameter[] parameters, CommandType commandType)
    {
        SqlDataReader reader = null;
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            using (SqlCommand command = new SqlCommand(procedure, connection))
            {
                connection.Open();
                if(parameters != null)
                {
                    if (commandType == CommandType.StoredProcedure)
                        command.Parameters.AddRange(parameters);
                }
                reader = command.ExecuteReader();
            }
        }
        return reader;
    }

here is the code where i am calling the SqlDataReader

using (SqlDataReader reader = SqlHelper.ExecuteReader("select top 10 username from users", null, System.Data.CommandType.Text))
        {
            Response.Write(reader.IsClosed); //This returns True

        }

Answer 1

EDIT

ExecuteReader with CommanBehavior ( automatically close connection after reading data)

To over come connection closing proble just make use of CommandBheviour

- CommandBehavior.CloseConnection 
   When you pass above values as argument to ExecuteReader 
     1. there is no need to close connection explicitly connection get close when you close your reader. 

code will be like this no need to close connection explicitly

public void CreateMySqlDataReader(string mySelectQuery,string myConnectionString) 
{
   SqlConnection myConnection = new SqlConnection(myConnectionString);
   SqlCommand myCommand = new SqlCommand(mySelectQuery, myConnection);
   myConnection.Open();
   SqlDataReader myReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection);
   while(myReader.Read()) 
   {
      Console.WriteLine(myReader.GetString(0));
   }
   myReader.Close();
   //Implicitly closes the connection because CommandBehavior.CloseConnection was specified.
}

---

its causing problem because you are closing connection

SqlReader always make use of open connection i.e live connection which is open when you use this

using (SqlConnection connection = new SqlConnection(connectionString)) 
        {
}

it dispose connection object which is used by reader object that why its returing IsColosed as true

If you wanto return value the objec than make use of DataTable which is disconnected data object and doens makse use of connection

Modified code

  public static DataTable ExecuteReader(string procedure, SqlParameter[] parameters, CommandType commandType)
  {
     DataTable dt = null;
     using (SqlConnection connection = new SqlConnection(connectionString))
     {
         using (SqlCommand command = new SqlCommand(procedure, connection))
         {
              connection.Open();
              if(parameters != null)
              {
            if (commandType == CommandType.StoredProcedure)
            command.Parameters.AddRange(parameters);
              }
                SqlDataAdapter da = new SqlDataAdapter(command);
                da.Fill(dt);
           }
         }
            return dt;
        }