using System;

using System.Linq.Expressions;

public class Program

{

    public static void Main()

    {

        string propertyForExpression = "Product.randomNumber";

        var lam = ToLambda<OrderEntity>(propertyForExpression).Compile();

​

        var oe = new OrderEntity();

        oe.Product = new ProductEntity()

        {

            randomNumber = 42

        };

​

        Console.WriteLine(lam(oe));

    }

​

​

    static Expression<Func<T, object>> ToLambda<T>(string propertyName)

    {

        var propertyNames = propertyName.Split('.');

        var parameter = Expression.Parameter(typeof(T));

        Expression body = parameter;

        foreach (var propName in propertyNames)

            body = Expression.Property(body, propName);

​

        var convertedResult = Expression.Convert(body, typeof(object));

​

        var func = Expression.Lambda<Func<T, object>>(convertedResult, parameter);

        return func;

    }

}

​

public class OrderEntity

{

    public int id { get; set; }

    public string name { get; set; }

    public ProductEntity Product { get; set; }

}

​

public class ProductEntity

{

    public int id { get; set; }

    public string productName { get; set; }

    public string description { get; set; }

    public int randomNumber { get; set; }

}