Comparing Object properties using reflection

I have two classes Address and Employee as follows:

 public class Address
{
    public string AddressLine1 { get; set; }
    public string AddressLine2 { get; set; }
    public string City { get; set; }
    public string State { get; set; }
    public string Zip { get; set; }
}

   public class Employee
    {
        public string FirstName { get; set; }
        public string MiddleName { get; set; }
        public string LastName { get; set; }
        public Address EmployeeAddress { get; set; }
    }

I have two employee instances as follows:

    var emp1Address = new Address();
    emp1Address.AddressLine1 = "Microsoft Corporation";
    emp1Address.AddressLine2 = "One Microsoft Way";
    emp1Address.City = "Redmond";
    emp1Address.State = "WA";
    emp1Address.Zip = "98052-6399";

    var emp1 = new Employee();
    emp1.FirstName = "Bill";
    emp1.LastName = "Gates";
    emp1.EmployeeAddress = emp1Address;


    var emp2Address = new Address();
    emp2Address.AddressLine1 = "Gates Foundation";
    emp2Address.AddressLine2 = "One Microsoft Way";
    emp2Address.City = "Redmond";
    emp2Address.State = "WA";
    emp2Address.Zip = "98052-6399";

    var emp2 = new Employee();
    emp2.FirstName = "Melinda";
    emp2.LastName = "Gates";
    emp2.EmployeeAddress = emp2Address;

Now how can I write a method which compares these two employees and returns the list of properties which have different values. So in this example I would like the result to be FirstName and Address.AddressLine1 .

Solution

You don't necessarily need reflection to perform the comparison. You can write a comparer class that takes two instances of Employee or Address, and compares each field that should match. For any that don't match, you can add a string (or PropertyInfo) element to some list to return to the caller.

Whether you return a PropertyInfo, MemberInfo, or just a string depends on what the caller needs to do with the result. If you actually need to visit the fields that contain differences, the PropertyInfo/MemberInfo may be better - but to just report the differences a string is probaby sufficient.

The main value of reflection would be to write a general purpose object comparer that could take two instances of any kind of object and compare their public fields and properties. This helps avoid writing repetetive comparison code over and over - but that doesn't seem like the case you're in.