DataGridView could be found

SqlDataAdapter da = new SqlDataAdapter(q0, constr);
DataTable dt = new DataTable();
da.Fill(dt);
GridView1.DataSource = dt;
GridView1.DataBind();

Quote:

'System.Windows.Forms.DataGridView' does not contain a definition for 'DataBind' and no extension method 'DataBind' accepting a first argument of type 'System.Windows.Forms.DataGridView' could be found (are you missing a using directive or an assembly reference?)