Hi
Please try replace your code with this one below:
string connectionString = "Data Source=MY-PC;Initial Catalog=TestDataBase;Integrated Security=SSPI";
string sqlQuery = "SELECT * From dataTable";
SqlConnection connection = new SqlConnection(connectionString);
SqlCommand dbCmd = new SqlCommand(sqlQuery, connection);
connection.Open();
DataSet ds = new DataSet();
SqlDataAdapter dataAdapter = new SqlDataAdapter();
dbAdapter.SelectCommand = dbCmd;
dataAdapter.Fill(ds,"dataTable");
dtGridView.DataSource = ds.Tables["dataTable"];
connection.Close();