Items.Add cannot be used because it is not the "DataSource" C# + WindowsForm

Question

I am trying to add an item to aircraftList ListBox and be able to click on it and on a detailsList TextBox display all information per item selected. However, I am using BindingList<AircraftDetails> Details = new BindingList<AircraftDetails>(); and AircraftClass which contains the following method:

public override string ToString()
    {
        List<string> builder = new List<string>();
        builder.add("something here like a variable");

which wil return all details to the detailsList textBox.

Now, the issue is that when I tried to do something like aircraftList.Items.Add("Test") it will show a error message showing this

I am at a loss for what to do, however I will provide the repository of my code that is hosted on gitHub so that you can better comprehend it. REPOSITORY

Answer 1

Thank you for posting your repository in support of your question. That made it easy to reproduce the issue. Making a minor change to your addaircraftButton_Click "should" do the trick.

public void addaircraftButton_Click(object sender, EventArgs e)
{
    FlightSetup addplane = new FlightSetup();
    AircraftDetails aircraftDetails = new AircraftDetails();
    using (addplane)
    {
        DialogResult result = addplane.ShowDialog();

        planeModel = addplane.planeModel_textbox.Text;
        airline = addplane.airline_textbox.Text;
        fuelG = double.Parse(addplane.fuel_textbox.Text);
        bag1 = int.Parse(addplane.carryonTextBox.Text);
        bag2 = int.Parse(addplane.checkedBagsTextBox.Text);

        object o = new AircraftDetails
        {
            AircraftModel = planeModel,
            Airline = airline,
            Fuel = fuelG, //TESTING
            OnBoardBags = bag1,
            CheckedBags = bag2,
            
            // Don't forget to assign TailNumber!
        };
        detailsList.Text = o.ToString();
    }

    //aircraftList.Items.Add(planeModel); // not working right here <--

    // Do this instead!
    Details.Add(aircraftDetails);
}

Obviously, you were very close to having the right code. The trick is that once you bind to a DataSource, you should work directly with that data Details.Add(aircraftDetails) and should no longer attempt to manipulate the UI control directly.

---

Optimized Solution

Consider that you could make FlightSetup responsible for creating a new AircraftDetails. If you remove all the event handlers that aren't doing anything, you get something like this:

public partial class FlightSetup : Form
{
    public FlightSetup()
    {
        InitializeComponent();
    }
    private void buttonFinish_Click(object sender, EventArgs e)
    {
        this.DialogResult = DialogResult.OK;
    }
    public AircraftDetails GetAircraftDetails()
    {
        var aircraftDetail = new AircraftDetails
        {
            // Please look into int.TryParse to make this more fault-tolerant.
            TailNumber = int.Parse(tailno_textbox.Text),
            AircraftModel = planeModel_textbox.Text,
            Airline = airline_textbox.Text,
            Fuel = double.Parse(fuel_textbox.Text),
            OnBoardBags = int.Parse(carryonTextBox.Text),
            CheckedBags = int.Parse(checkedBagsTextBox.Text),
        };
        return aircraftDetail;
    }
}

---

Now, back in the main form you have a squeaky-clean method:

public void addaircraftButton_Click(object sender, EventArgs e)
{
    using (FlightSetup addplane = new FlightSetup())
    {
        DialogResult result = addplane.ShowDialog();

        if(result == DialogResult.OK)
        {
            AircraftDetails aircraftDetails = addplane.GetAircraftDetails();
            Details.Add(aircraftDetails);
            detailsList.Text = aircraftDetails.ToString();
            aircraftList.SelectedItem = aircraftDetails;
        }
    }
}

When your code is run after making these changes, here is the result: