public class InitSQL
    {
        public SqlConnection con;
        public SqlDataAdapter adapter;
        public DataSet ds;

        public void MySQLConnect(string priemCommandSQL)
        {
            con = new SqlConnection();
            con.ConnectionString = MyClassGlobal.connectString; //Строка подключения из другого класса
            ds = new DataSet();
            con.Open();
            adapter = new SqlDataAdapter(priemCommandSQL, con);            
            
            try
            {
                adapter.Fill(ds, "table");
            }
            catch
            {
                MessageBox.Show(@"Не могу подключиться к базе !!! ");
            }
            finally
            {
                con.Close();
            }
        }

 private void DepartmentsDirectoryBasic_Load(object sender, EventArgs e)
        {
            InitSQL initSql = new InitSQL();
            initSql.MySQLConnect("Select * from departments");
            dataGridView1.DataSource = initSql.ds.Tables["table"];
        }

 private void DepartmentsDirectoryBasic_Load(object sender, EventArgs e)
        {
            InitSQL initSql = new InitSQL();
            initSql.MySQLConnect("Select * from departments");
            dataGridView1.DataSource = initSql.ds.Tables["table"].Columns["name_dep"];
        }