Navigate from a view model in xamarin forms - xamarin.forms

Question

I am trying to push a view in xamrian forms from the view model but I cant appear to get it to work its really when the user has entered correct username and password it should show the home page.
You will see I have the on submit command this is just mock data at present so dont mind the design of code at this stage will change.
Usually I would use
var stocktakepage = new StockTake();
await Navigation.PushAsync(stocktakepage);
But the model does not no about the navigation stack in the class is their another way to navigate from the view model thanks.
public class LoginViewModel : INotifyPropertyChanged
{
public Action DisplayInvalidLoginPrompt;
public event PropertyChangedEventHandler PropertyChanged = delegate { };
private string email;
public string Email
{
get { return email; }
set
{
email = value;
PropertyChanged(this, new PropertyChangedEventArgs("Email"));
}
}
private string password;
public string Password
{
get { return password; }
set
{
password = value;
PropertyChanged(this, new PropertyChangedEventArgs("Password"));
}
}
public ICommand SubmitCommand { protected set; get; }
public LoginViewModel()
{
SubmitCommand = new Command(OnSubmit);
}
public void OnSubmit()
{
if (email != "handheld1" || password != "test123")
{
DisplayInvalidLoginPrompt();
}else
{
}
}
}

Answer 1

I found the answer here
https://forums.xamarin.com/discussion/21822/call-navigation-pushasync-from-viewmodel But also on my main login page i have this. What this does is act like a delegate and allows you to push the view from the original calling page.
public Login()
{
var vm = new LoginViewModel();
this.BindingContext = vm;
Password.Completed += (object sender, EventArgs e) =>
{
vm.SubmitCommand.Execute(null);
};
}

Answer 2

You can also use the below in order to Navigate from your ViewModel. You can do this for each type of page you want. Check below examples:
await App.Current.MainPage.Navigation.PushAsync(new PageName());
also
await App.Current.MainPage.Navigation.PushModalAsync(new NavigationPage(new PageName()) { BarBackgroundColor = Color.FromHex("#101010"), BarTextColor = Color.White, }, true);