Xamarin Essentials

UnitConverters

//UnitConverterPageViewModel

  private string _kilometers;

        public string Kilometers
        {
            get { return _kilometers; }
            set
            {
                SetProperty(ref _kilometers, value);

            }
        }
        public DelegateCommand<object> ConvertToKilometer { get; set; }
        public UnitConverterPageViewModel()
        {
            ConvertToKilometer = new DelegateCommand<object>(ToKilometers);
        }

        private void ToKilometers(object Miles)
        {
            _kilometers = UnitConverters.MilesToKilometers(Convert.ToDouble(Miles)).ToString();
             RaisePropertyChanged("Kilometers");
        }

//UnitConverterPage

 public partial class UnitConverterPage : ContentPage
    {
        UnitConverterPageViewModel objUnitConverterViewModel;
        public UnitConverterPage()
        {
            InitializeComponent();
            this.BindingContext = objUnitConverterViewModel = new UnitConverterPageViewModel();
        }

        private void Entry_TextChanged(object sender, TextChangedEventArgs e)
        {
            if(e.OldTextValue!=null)
            {
                return;
            }
            if (e.NewTextValue != null)
            {
                double textValue=Convert.ToInt64(e.NewTextValue);
                objUnitConverterViewModel.ConvertToKilometer.Execute(textValue);

            }
        }
    }
    
    //Xaml
    
      <StackLayout Margin="20">
            <Label Text="Miles" ></Label>
            <Entry Text="{Binding Miles}" TextChanged="Entry_TextChanged"/>

            <Label Text="Killometers"/>
            <Label Text="{Binding Kilometers}"/>

        </StackLayout>