I have a custom Order class, groups of which are stored in List<Order> and a DataGridView. I think the problem is in my implementation so here's how I'm using it:

In the form enclosing DataGridView (as OrdersDataGrid):

public partial class MainForm : Form
{

    public static List<Order> Orders;

    public MainForm()
    {
        // code to populate Orders with values, otherwise sets Orders to new List<Order>();
        OrdersDataGrid.DataSource = Orders;
    }

Then in another form that adds an Order:

// Save event
public void Save(object sender, EventArgs e) {
    Order order = BuildOrder(); // method that constructs an order object from form data
    MainForm.Orders.Add(order);
}

From what I can tell from the console this is added successfully. I thought the DataGrid would be updated automatically after this since Orders has changed - is there something I'm missing?

The DataGrid accepts the class since it generates columns from the members.