Is there any difference between `new object()` and `new {}` in c#?

问题

in c#,

var x = new {};

declares an anonymous type with no properties. Is this any different from

var x = new object();

?

回答1:

Yes, the types used are different. You can tell this at compile-time:

var x = new {};
// Won't compile - no implicit conversion from object to the anonymous type
x = new object(); 

If you're asking whether new{} is ever useful - well, that's a different matter... I can't immediately think of any sensible uses for it.

回答2:

Well, for starters, object is an actual, non-anonymous type...if you do x.GetType() on the 2nd example, you'll get back System.Object.

回答3:

Along with the return from GetType as mentioned, x would not be of type object, so you would not be able to assign an object type to that variable.

        var x = new { };
        var y = new object();

        //x = y; //not allowed
        y = x; //allowed

回答4:

Jon Skeet's answer was mostly what I wanted, but for the sake of completeness here are some more differences, gained from reflector:

new {} overrides three methods of object :

1. Equals - as mentioned in other answers, new object and new {} have different types, so they are not equal.
2. GetHashCode returns 0 for new {} (but why would you put it in a hash table anyway?)
3. ToString prints "{}" for new {}

Unfortunately I can't think of a practical application for all this. I was just curious.

来源：https://stackoverflow.com/questions/1027997/is-there-any-difference-between-new-object-and-new-in-c