New Post: Update While Show Dialog is Open

I have a scenario and wanted to know if its possible to do something while the ShowDialog is open. Below is the current code I have:

        this.NumericViewModel = new NumericKeypadViewModel(this.Quantity);
        bool? dialogResult = this.windowManager.ShowDialog(this.NumericViewModel, null, settings);

        if (dialogResult == true)
        {
            this.Quantity = this.NumericViewModel.InputDataEntered; 
        }

However I want to update Quantity every time InputDataEntered from NumericViewModel changes while the dailog is open. Is it possible to do that?