public FirstPageViewModel(INavigationService navigationService, IGeoCoder geoCoder)
{
Address.Value = "東京都渋谷区";
NextCommand = Address.Select(x => !string.IsNullOrEmpty(x)).ToReactiveCommand();
NextCommand.Subscribe(async _ =>
{
var res = await geoCoder.Forward(Address.Value);
if (res != null)
{
await navigationService.NavigateAsync($"SecondPage?lat={res.Latitude}&lng={res.Longitude}&title={res.DisplayName}");
}
});
}