How to bind a ListBox to a property of type List on an object?

Question

I have a form with a DataGridView showing a list of customers, and some text boxes below showing details of the customer selected in the grid.

I have a Customer class and a CustomerList class of Customer objects, and a BindingSource with DataSource set to a CustomerList. The DataSource of the grid is this BindingSource.

Binding the textboxes is easy - I just use the same BindingSource and specify the property of Customer I want to display. The problem is that one of the properties of Customer is a list itself, and I want to display this list in e.g. a ListBox.

How can I accomplish showing this list in a ListBox using databinding, and have the list updated each time I click on a customer in the grid?

Answer 1

You can use a linked BindingSource. A full example is below, but the only interesting bit is:

        BindingSource outer = new BindingSource(customers, ""),
            inner = new BindingSource(outer, "Orders");

here's the code:

using System;
using System.Collections.Generic;
using System.Windows.Forms;
class Order
{
    public string OrderRef { get; set; }
    public override string ToString() {
        return OrderRef;
    }
}
class Customer
{
    public string Name {get;set;}
    public Customer() { Orders = new List<Order>(); }
    public List<Order> Orders { get; private set; }
}
static class Program
{
    [STAThread]
    static void Main()
    {
        List<Customer> customers = new List<Customer> {
            new Customer {Name = "Fred", Orders = {
                new Order { OrderRef = "ab112"},
                new Order { OrderRef = "ab113"}
            }},
            new Customer {Name = "Barney", Orders = {
                new Order { OrderRef = "ab114"}
            }},
        };
        BindingSource outer = new BindingSource(customers, ""),
            inner = new BindingSource(outer, "Orders");
        Application.Run(new Form
        {
            Controls =
            {
                new DataGridView {
                    Dock = DockStyle.Fill,
                    DataSource = outer},
                new ListBox {
                    Dock = DockStyle.Right,
                    DataSource = inner
                }
            }
        });
    }
}

Answer 2

I assume that property is a list of Strings.

All you have to do as you did for text, do:

listBox1.DataSource = ListOfProperties;

Just change the List as the customer changes. If you post the code it will be more easy to know what the real issue is.