How to easily merge two anonymous objects with different data structure?

Question

I would like to merge these two anonymous objects:

var man1 = new {
    name = new {
        first = "viet"
    },
    age = 20
};

var man2 = new {
    name = new {
        last = "vo"
    },
    address = "123 street"
};

Into a single one:

var man = new {
    name = new {
        first = "viet",
        last = "vo"
    },
    age = 20,
    address = "123 street"
};

I looked for a solution but found nothing clever.

Answer 1

There's nothing built-in in the C# language to support your use case. Thus, the question in your title needs to be answered with "Sorry, there is no easy way".

I can offer the following alternatives:

1. Do it manually:

   var man = new {
       name = new {
           first = man1.name.first,
           last = man2.name.first
       },
       age = man1.age,
       address = man2.address
   };
   

2. Use a class instead of an anonymous type for the resulting type (let's call it CompleteMan). Then, you can

   • create a new instance var man = new CompleteMan(); ,
   • use reflection to collect the properties and values from your "partial men" (man1 and man2),
   • assign those values to the properties of your man.

   It's "easy" in the sense that the implementation will be fairly straight-forward, but it will still be a lot of code, and you need to take your nested types (name) into account.

   If you desperately want to avoid non-anonymous types, you could probably use an empty anonymous target object, but creating this object (var man = new { name = new { first = (string)null, last = (string)null, ...) is not really less work than creating a class in the first place.

3. Use a dedicated dynamic data structure instead of anonymous C# classes:

   • The Newtonsoft JSON library supports merging of JSON objects.
   • Dictionaries can also be merged easily.
   • ExpandoObjects can be merged easily as well.