using System;

using System.Reflection;

using System.Linq.Expressions;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("*** Regular nullable DateTime ***");

        Console.WriteLine(GetPropertyInfo<TestClass, DateTime?>(x => x.DtNullable, default(DateTime?)));

        Console.WriteLine("\n*** Conversion of DateTime to nullable DateTime ***");

        Console.WriteLine(GetPropertyInfo((TestClass x) => x.Dt, default(DateTime?)));

    }

    // Old

    public static PropertyInfo GetPropertyInfo<T>(Expression<Func<T, object>> expression)

    {

        MemberExpression me;

        switch (expression.Body.NodeType)

        {

            case ExpressionType.Convert:

            case ExpressionType.ConvertChecked:

            var ue = expression.Body as UnaryExpression;

            Console.WriteLine("Expression body type" + expression.Body.GetType());

            Console.WriteLine("Unary expression: " + ue != null);

            me = ((ue != null) ? ue.Operand : null) as MemberExpression;

            break;

            default:

            me = expression.Body as MemberExpression;

            break;

        }

        if (me == null)

        {

            throw new InvalidOperationException("Expression does not refer to a property: " + expression.ToString());

        }

        return (PropertyInfo)me.Member;

    }

    // New

    public static PropertyInfo GetPropertyInfo<T, TProp>(Expression<Func<T, TProp>> expression, TProp myVal)

    {

        Console.WriteLine("Value parameter: " + typeof(TProp));

        return GetPropertyInfo(convertToObjectExpression(expression));

    }

    // Conversion New -> Old

    private static Expression<Func<T, object>> convertToObjectExpression<T, TProp>(Expression<Func<T, TProp>> expression)

    {

        return Expression.Lambda<Func<T,object>>(

            Expression.Convert(expression.Body, typeof(object)),

            expression.Parameters);

    }

}

​

public class TestClass {

    public DateTime Dt { get; set; }

    public DateTime? DtNullable { get; set; }   

}