using System;

public class Program

{

    public static void Main()

    {

        var foo = new Foo() 

        {

            AssetId = "SomeString",

            VIN = "SOMEVIN",

            IMEI = "LETSPRETENDIM15CHARS"

        };

        Console.WriteLine(foo.IsRegistered);

    }

}

​

public class Foo

{

    public string AssetId { get; set; } = string.Empty;

    public string VIN { get; set; } = string.Empty;

    public string IMEI { get; set; } = string.Empty;

    public bool IsRegistered => !string.IsNullOrEmpty(IMEI);

}