MultiTerm/MultiTerm.Core/ViewModel/ShellViewModel.cs

using Common.StartupHelpers;
using CommunityToolkit.Mvvm.ComponentModel;
using System.Collections.ObjectModel;

namespace MultiTerm.Core.ViewModel;

public partial class ShellViewModel : ObservableObject
{
    private readonly IAbstractFactory<SendReceiveViewModel> sendReceiveViewModelFactory;

    [ObservableProperty]
    private string title = "ShellView Test";

    [ObservableProperty]
    private ObservableCollection<ITerminalViewModel> terminalViewModels = new();

    [ObservableProperty]
    private ITerminalViewModel? selectedTerminalViewModel;

    public ShellViewModel(IAbstractFactory<SendReceiveViewModel> sendReceiveViewModelFactory)
    {
        this.sendReceiveViewModelFactory = sendReceiveViewModelFactory;
        // create a new terminal
        this.AppendTerminal(this.sendReceiveViewModelFactory.Create());
    }

    public void AppendTerminal(ITerminalViewModel newTerminal)
    {
        // guard null value
        if(newTerminal == null)
        {
            return;
        }
        // add to collection and set as selected
        this.TerminalViewModels.Add(newTerminal);
        this.SelectedTerminalViewModel = newTerminal;
    } 
}