Wpf: combobox, SQL server and MVVM

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C#

WPF

MVVM

Hello.

I am trying to simply populate a ComboBox with data from a Sql server table column (adhering to the MVVM design pattern), and do not understand why it is not working. I am binding it to a BindableCollection (Stylet framework), which is basically an ObservableCollection.
There is automatic coupling between the View and the ViewModel (Stylet does this).

This is my method:

public void FillComboBoxLicenseHolders() {

    try {

        DataSet ds = new DataSet();

        using (SqlConnection sqlCon = new SqlConnection(ConnectionString.connectionString)) {

            SqlDataAdapter sqlDA = new SqlDataAdapter();
            sqlDA.SelectCommand = new SqlCommand("select Foretaksnavn from tblLicenseHolder", sqlCon);
            sqlDA.Fill(ds);
        }

        DataTable dt = new DataTable();
        dt = ds.Tables[0];

        for (int i = 0; i < dt.Rows.Count; i++) {

            DataRow dr = dt.NewRow();
            dr = dt.Rows[i];
            LicenseHolder licenseHolder = new LicenseHolder();
            licenseHolder.Foretaksnavn = dr["Foretaksnavn"].ToString();

            LicenseHolders.Add(licenseHolder);
        }

    } catch (Exception ex) {

        MessageBox.Show(ex.Message, "Message", MessageBoxButton.OK, MessageBoxImage.Information);
    }
}

This is how I instantiate my BindableCollection:

private BindableCollection<LicenseHolder> _licenseHolders;
public BindableCollection<LicenseHolder> LicenseHolders {

    get => _licenseHolders;
    set => SetAndNotify(ref this._licenseHolders, value);
}

public TripViewModel(IWindowManager windowManager) {

    this.windowManager = windowManager;
    LicenseHolders = new BindableCollection<LicenseHolder>();
}

This is my ComboBox in the XAML:

<ComboBox Name="cbLicenseHolder" Canvas.Left="50" Canvas.Top="204" Width="291"
          ItemsSource="{Binding LicenseHolders, Mode=TwoWay}"
          Loaded="{s:Action FillComboBoxLicenseHolders}"/>

What I have tried:

I've spent the better part of a day trying to Google my way through this..

When I run my app, there's no error message, but the ComboBox displays no results.
If I debug and put a break point, I can see that it does indeed read the sql server column data, but it is still not showing.

Any ideas?