建立与sql server的连接时发生网络相关错误或特定于实例的错误

Question

这是我尝试在Visual C＃2010下调试应用程序时出现的错误

我编写该代码以从数据库表中检索某些行，我已将两个众所周知的数据库Pubs和Northwind附加到db explorer，但错误仍然存​​在

class Author
{
    SqlConnection _pubConnection;
    string _connString;

    public Author()
    {
        _connString = "Data Source=./INSTANCE2;Initial Catalog=pubs;Integrated Security=True";
        _pubConnection = new SqlConnection();
        _pubConnection.ConnectionString = _connString;
    }

    public int CountAuthors()
    {
        try
        {
            SqlCommand pubCommand = new SqlCommand();
            pubCommand.Connection = _pubConnection;
            pubCommand.CommandText = "Select Count(au_id) from authors";
            _pubConnection.Open();
            return (int)pubCommand.ExecuteScalar();
        }
        catch (SqlException ex)
        {
            throw ex;
        }
        finally
        {
            if (_pubConnection != null)
            {
                _pubConnection.Close();
            }
        }
    }
}

static void Main(string[] args)
{
   try
   {
      Author author = new Author();
      Console.WriteLine(author.CountAuthors());
      Console.ReadLine();
   }
   catch (Exception ex)
   {
      Console.WriteLine(ex.Message);
      Console.ReadLine();
   }
}

Answer 1

连接字符串不正常，我纠正它并且工作正常