when i am using xamarin MVVM. so how to handle Device Back(Hardware back button) in view model

Question

I am creating one app in xamarin cross platform with MVVM, I want to handle device back navigation so how can i handle it? please help me.

Thanks in advance

Answer 1

Well, that's quite simple actually just add a command in your VM and call that command from your View when you need to handle this event!

In your View

protected override bool OnBackButtonPressed()
{
   var vm = (ViewModel)BindingContext;
   if(vm.MyBackPressCommand.CanExecute())  // You can add parameters if any
     {
         MyBackPressCommand.Execute(); // You can add parameters if any
     }
}

Also, define this in your ViewModel

public ICommand MyBackPressCommand { get; set; }

And also this needs to be initialized(constructor) like below:

MyBackPressCommand= new Xamarin.Forms.Command(()=>{});

You can use inheritance to make this globally available for all derived versions of your View/ViewModel