is order of field important in anonymous types automatic initialization?
anonymous-types, c#
Solution
Yes, it's important.
Two anonymous type initializers use the same auto-generated type if the property names and types are the same, in the same order.
The order becomes relevant when hashing; it would have been possible for the type to be generated with a consistent order for calculating a hash value, but it seems simpler to just include the property order as part of what makes a type unique.
See section 7.5.10.6 of the C# 3 spec for details. In particular:
Within the same program, two anonymous object initializers that specify a sequence of properties of the same names and compile-time types in the same order will produce instances of the same anonymous type.
Problem
I got a scenario to create the anonymous list from the anonymous types, and i achieved that using ``` public static List<T> MakeList<T>(T itemOftype) { List<T> newList = new List<T>(); return newList; } static void Main(string[] args) { //anonymos type var xx = new { offsetname = x.offName, RO = y.RO1 }; //anonymos list var customlist = MakeList(xx); //It throws an error because i have given the wrong order customlist.Add(new { RO = y.RO2, offsetname = x.offName }); customlist.Add(new { RO = y.RO3, offsetname = x.offName }); //but this works customlist.Add(new { offsetname = x.offName, RO = y.RO2 }); customlist.Add(new { offsetname = x.offName, RO = y.RO3 }); } ``` these are the error messages System.Collections.Generic.List.Add(AnonymousType#1)' has some invalid arguments Argument '1': cannot convert from 'AnonymousType#2' to 'AnonymousType#1' whats the reason behind that??