Question

I’m using var abc = new { id = 0 }; in my C# code without knowing what type it exactly is!

Is is simply called an object? Is it a particular type of object?

I want to know coz I don’t know how to add fields to this kind of object

Quick example:
I have var abc = new { id = 0 }; and I want to add to abc the field name = "david"

Answer 1

It is an anonymous type, that is, it does not have a type that you can use in code (though the compiler generates one).

MSDN says:

The type name is generated by the compiler and is not available at the source code level.

If you want to add a property, you can simply do so:

var abc = new { id = 0, name = "david" };