Xamarin Form Fluent Binding

Example.cs

namespace Examples
{
	public class LoginView
	{
		private Entry _txtUserName;
		private Entry _txtPassword;
		private Button _btnLogin;

		public LoginView ()
		{
			var set = this.CreateBindingSet<LoginViewModel> ();
			set.Bind (_txtUserName).For (t => t.Text).To (vm => vm.UserName);
			set.Bind (_txtPassword).For (t => t.Text).To (vm => vm.Password);
			set.Bind (_btnLogin).For (b => b.Command).To (vm => vm.LoginCommand);
			/*Or
			set.Bind (_txtUserName).For (Entry.TextProperty).To (vm => vm.UserName);
			set.Bind (_txtPassword).For (Entry.TextProperty).To (vm => vm.Password);
			set.Bind (_btnLogin).For (Button.CommandProperty).To (vm => vm.LoginCommand);
			*/
			set.Apply ();
		}

	}
}

IXAppliable.cs

using System;
namespace XForm
{
	public interface IXAppliable
	{
		void Apply ();
	}
}

XFluentBindingDescription.cs

using System;
using System.Linq.Expressions;
using Xamarin.Forms;
using System.Reflection;
using System.Linq;
using System.Diagnostics;

namespace XForm
{
	public class XFluentBindingDescription<TTarget, TSource> : IXAppliable where TTarget : BindableObject
	{
		private readonly TTarget _self;

		private BindableProperty _targetProperty;
		private Expression<Func<TSource, object>> _sourceProperty;
		private BindingMode _mode;
		private IValueConverter _converter;
		private object _converterParameter;
		private string _stringFormat;


		public XFluentBindingDescription (TTarget self)
		{
			if (self == null)
				throw new ArgumentNullException (nameof (self));
			_self = self;
			_mode = BindingMode.Default;
		}

		public XFluentBindingDescription<TTarget, TSource> For (BindableProperty targetProperty)
		{
			_targetProperty = targetProperty;
			return this;
		}

		public XFluentBindingDescription<TTarget, TSource> For (Expression<Func<TTarget, object>> targetPropertyPath)
		{
			string targetPropertyName = (targetPropertyPath.Body as MemberExpression).Member.Name + "Property";
			return For (targetPropertyName);
		}

		public XFluentBindingDescription<TTarget, TSource> For (string targetPropertyName)
		{
			FieldInfo fieldInfo = null;
			Type type = _self.GetType ();

			do {
				fieldInfo = type.GetRuntimeField (targetPropertyName);
				if (fieldInfo != null)
					break;
				type = type.GetTypeInfo ()?.BaseType;
			}
			while (type != null);

			if (fieldInfo == null)
				throw new InvalidOperationException ("Not found BindableProperty: " + targetPropertyName);
			_targetProperty = (Xamarin.Forms.BindableProperty)fieldInfo.GetValue (null);
			return this;
		}

		public XFluentBindingDescription<TTarget, TSource> To (Expression<Func<TSource, object>> sourceProperty)
		{
			_sourceProperty = sourceProperty;
			return this;
		}

		public XFluentBindingDescription<TTarget, TSource> TwoWay ()
		{
			return this.Mode (BindingMode.TwoWay);
		}

		public XFluentBindingDescription<TTarget, TSource> OneWay ()
		{
			return this.Mode (BindingMode.OneWay);
		}

		public XFluentBindingDescription<TTarget, TSource> OneWayToSource ()
		{
			return this.Mode (BindingMode.OneWayToSource);
		}

		public XFluentBindingDescription<TTarget, TSource> Mode (BindingMode mode)
		{
			_mode = mode;
			return this;
		}


		public XFluentBindingDescription<TTarget, TSource> WithConversion (IValueConverter converter, object converterParameter = null)
		{
			_converter = converter;
			_converterParameter = converterParameter;

			return this;
		}

		public XFluentBindingDescription<TTarget, TSource> WithStringFommat (string stringFormat)
		{
			_stringFormat = stringFormat;
			return this;
		}

		void IXAppliable.Apply ()
		{
			if (_self == null) {
				throw new ArgumentNullException ("self");
			}
			if (_targetProperty == null) {
				throw new ArgumentNullException ("targetProperty");
			}
			if (_sourceProperty == null) {
				throw new ArgumentNullException ("sourceProperty");
			}
			Binding binding = Binding.Create<TSource> (_sourceProperty, _mode, _converter, _converterParameter, _stringFormat);
			_self.SetBinding (_targetProperty, binding);
		}

	}
}

XFluentBindingDescriptionSet.cs

using System;
using Xamarin.Forms;
using XForm;
using System.Collections.Generic;

namespace XForm
{
	public class XFluentBindingDescriptionSet<TSource> : IXAppliable
	{
		private readonly List<IXAppliable> _applicables;

		public XFluentBindingDescriptionSet ()
		{
			_applicables = new List<IXAppliable> ();
		}

		public XFluentBindingDescription<TChildTarget, TSource> Bind<TChildTarget> (TChildTarget childTarget) where TChildTarget : BindableObject {
			var desc = new XFluentBindingDescription<TChildTarget, TSource> (childTarget);
			_applicables.Add (desc);
			return desc;
		}

		public  void Apply ()
		{
			foreach (var applicable in _applicables)
				applicable.Apply ();
		}
	}
}

XFluentExtenstion.cs

using System;
using Xamarin.Forms;

namespace XForm
{
	public static class XFluentExtenstion
	{
		public static XFluentBindingDescriptionSet<TSource> CreateBindingSet<TSource> (this object owner){
			return new XFluentBindingDescriptionSet<TSource> ();
		}
	}
}