luismts

public class BooleanToObjectConverter : BindableObject, IValueConverter
{
    public static readonly BindableProperty TrueObjectProperty = BindableProperty.Create<BooleanToObjectConverter, Object>(x => x.TrueObject, null);
    public static readonly BindableProperty FalseObjectProperty = BindableProperty.Create<BooleanToObjectConverter, Object>(x => x.FalseObject, null);

    public object FalseObject
    {
        get { return GetValue(FalseObjectProperty); }
        set { SetValue(FalseObjectProperty, value); }
    }

luismts

var grid = new Grid();

var label = new Label { Text = "Code:" };
grid.Children.Add(label, 0, 1);

var entry = new Entry 
{ 
   Placeholder = "Enter number", 
   Keyboard = Keyboard.Numeric, 
   BackgroundColor = Color.AliceBlue, 

luismts

• Reducing executable size: http://developer.xamarin.com/guides/cross-platform/deployment,_testing,_and_metrics/memory_perf_best_practices/#Reducing_Executable_Size

• Use the linker (iOS [1], Android [2]) to remove unnecessary code from your assemblies [1] https://developer.xamarin.com/guides/ios/advanced_topics/linker [2] https://developer.xamarin.com/guides/android/advanced_topics/linking

• Reference third-party libraries judiciously

• Applying constraints to generics may reduce app size, since less code would need to be included (haven’t verified this)

luismts

...
new Entry { Placeholder = "Sigueme en las redes @luismatosluna", Keyboard = Keyboard.Numeric,
            Margin = myMargin, HeightRequest = 20 }
            .Grid.Row(2) .Grid.ColumnSpan(2)
            .Bind(nameof(vm.RegistrationCode), BindingMode.TwoWay),
...

luismts

...
<Entry Placeholder="Sigueme en las redes @luismatosluna" Keyboard="Numeric"
       Margin="{StaticResource myMargin}" HeightRequest="20"
       Grid.Row="2" Grid.ColumnSpan="2"
       Text="{Binding RegistrationCode, Mode=TwoWay}" />
...

luismts

...
new Entry { Placeholder = "Sigueme en las redes @luismatosluna", Keyboard = Keyboard.Numeric }            
            .Grid.Row(2) .Grid.ColumnSpan(2) .Margin(myMargin) .Height(20) 
            .Bind(nameof(vm.RegistrationCode), BindingMode.TwoWay),
...

luismts

<ContentPage ...
             Visual="Material">
    ...
</ContentPage>  

luismts

...
Forms.SetFlags("Visual_Experimental");
...

luismts

/// XF Project
namespace UsingDependencyService
{
    public interface IToDo {
        void ToDo (); //note that interface members are public by default
    }
}

namespace UsingDependencyService.Service
{

luismts

public class RestService : IRestService
{
  HttpClient client;
  ...

  public RestService ()
  {
    client = new HttpClient (); // Creating the HTTPClient Object
  }