C# winforms: Bind ListBox SelectedItem to another ListBox

Question

I have this model:

class Car
{
  string CrewNickname { get; set; }
  Líst<string> RacersNames { get; set; }
}

class StartingField
{
  List<Car> Cars { get; set; }
}

What I need is to display cars in one listbox and when I click on any car, to display names of its racers in the second listbox. I also need to be able to add/remove cars and add/remove/edit racers.

I haven't found any suitable tutorial or question, but I think this must be possible to create.

Any help is appreciated.

Answer 1

You should use the OnSelectedIndex method for the first listbox, that raises the SelectedValueChanged event. Then populate the second listbox based on the selected index of the first listbox.

Answer 2

You can do something like this:

• Use two BindingSource objects to link each Car in the list to its list of RacersNames
• Add a Property used to show each Car name in the first ListBox (the CarID Property is there just to show the use of ValueMember )
• You need public Properties, of course.

BindingSource bsCars = null;
BindingSource bsRacers = null;
StartingField startingField = null;

public class Car
{
    public Car(string carName, int carID) { CarName = carName; CarID = carID; }
    public string CarName { get; }
    public int CarID { get; }
    public List<string> RacersNames { get; set; } = new List<string>();
}

public class StartingField
{
    public List<Car> Cars { get; } = new List<Car>();
}

The initialize the source of data and set the DataSource of the BindingSource objects and the ListBoxes.
Since the second BindingSource is linked to the RacersNames property of the first BindingSource, when you select a car name in the first ListBox, the second BindingSource will update its content and, as a consequence, the ListBox bound to it will show the list of RacersNames related to the new selection.

Elements can be added or removed from both lists.

You can add this code to the Load event (or OnLoad() override) of a Form.

startingField = new StartingField();
var c1 = new Car("Car1", 1) { RacersNames = { "Racer1", "Racer2", "Racer3" } };
var c2 = new Car("Car2", 2) { RacersNames = { "Racer4", "Racer5", "Racer6" } };
var c3 = new Car("Car3", 3) { RacersNames = { "Racer7", "Racer8", "Racer9" } };

startingField.Cars.AddRange(new[] { c1, c2, c3});

bsCars = new BindingSource(startingField.Cars, "");
bsRacers = new BindingSource(bsCars, "RacersNames");

listBox1.DisplayMember = "CarName";
listBox1.ValueMember = "CarID";
listBox1.DataSource = bsCars;
listBox2.DataSource = bsRacers;