How to pass data when navigating through TabBar?

Question

To pass data beetwen viewmodels when navigating I use query parameters (IQueryAttributable), i.e.:

NavigationParameters[nameof(SomeProperty)] = SomeProperty;
await Shell.Current.GoToAsync("SomePage", NavigationParameters);

It works as it should be working, but I wish to put SomePage into a TabBar:

<TabBar>
    <ShellContent Route="SomePage"
        ContentTemplate="{DataTemplate local:SomePage}"/>
    ...
</TabBar>

Is there a way to pass data when user click/tap SomePage icon on the tab bar? Is there some event for that so I could hook up GoToAsync method? Or maybe there is another way than query to pass data beetwen viewmodels?

Answer 1

MauiProgram.cs:

public static class MauiProgram
{
    public static MauiApp CreateMauiApp()
    {
        var builder = MauiApp.CreateBuilder();
        builder.UseMauiApp<App>();
        builder.Services
            .AddSingleton<Page_1>
            .AddSingleton<ViewModel_1>
            .AddSingleton<Page_2>
            .AddSingleton<ViewModel_2>
            .AddSingleton<ISharedDataInterface, SharedDataInterfaceImplementation>();
        return builder.Build();
    }
}

Page_1.xaml.cs:

public partial class Page_1 : ContentPage
{
    public LogoPage(ViewModel_1 viewModel_1)
    {
        BindingContext = viewModel_1;

        InitializeComponent();
    }
}

Page_2.xaml.cs:

public partial class Page_2 : ContentPage
{
    public LogoPage(ViewModel_2 viewModel_2)
    {
        BindingContext = viewModel_2;

        InitializeComponent();
    }
}

ViewModel_1.cs:

public class ViewModel_1
{
    public ViewModel_1(ISharedDataInterface sharedDataInterfaceImplementation)
    {
        ...
    }
}

ViewModel_2.cs:

public class ViewModel_2
{
    public ViewModel_2(ISharedDataInterface sharedDataInterfaceImplementation)
    {
        ...
    }
}