DynamicPropertyAccessor.cs

using System;
using System.Diagnostics.Contracts;
using System.Linq.Expressions;
using System.Reflection;

public class DynamicPropertyAccessor<TObject, TProperty>
{
	public string Name { get; private set; }
	public Type PropertyType { get; private set; }

	private Lazy<Func<TObject, TProperty>> Getter { get; set; }
	private Lazy<Action<TObject, TProperty>> Setter { get; set; }

	public DynamicPropertyAccessor(PropertyInfo targetProperty)
	{
		Contract.Requires<ArgumentNullException>(targetProperty != null);

		Name = targetProperty.Name;
		PropertyType = targetProperty.PropertyType;

		var objectParam = Expression.Parameter(typeof(TObject), "object");
		var specificObject = Expression.Convert(objectParam, targetProperty.ReflectedType);
		var property = Expression.Property(specificObject, targetProperty);

		if (targetProperty.CanRead)
		{
			// Getter
			var convertToObject = Expression.Convert(property, typeof(TProperty));
			var getter = Expression.Lambda<Func<TObject, TProperty>>(convertToObject, objectParam);
			Getter = new Lazy<Func<TObject, TProperty>>(getter.Compile);
		}

		if (targetProperty.CanWrite)
		{
			// Setter
			var valueParam = Expression.Parameter(typeof(TProperty), "value");
			var value = Expression.Convert(valueParam, PropertyType);
			var assign = Expression.Assign(property, value);
			var setter = Expression.Lambda<Action<TObject, TProperty>>(assign, objectParam, valueParam);
			Setter = new Lazy<Action<TObject, TProperty>>(setter.Compile);
		}
	}

	public TProperty this[TObject obj]
	{
		get
		{
			Contract.Requires(obj != null);

			if (Getter == null)
				throw new InvalidOperationException(string.Format("The property '{0}', represented by this DynamicPropertyAccessor, is not readable.", Name));

			return Getter.Value(obj);
		}
		set
		{
			Contract.Requires(obj != null);

			if (Setter == null)
				throw new InvalidOperationException(string.Format("The property '{0}', represented by this DynamicPropertyAccessor, is not writeable.", Name));

			Setter.Value(obj, value);
		}
	}
}

public class DynamicPropertyAccessor : DynamicPropertyAccessor<object, object>
{
	public DynamicPropertyAccessor(PropertyInfo targetProperty) : base(targetProperty) { }
}