Why is DateTime.Now a property and not a method?

Question

After reading this blog entry : http://wekeroad.com/post/4069048840/when-should-a-method-be-a-property,

I'm wondering why Microsoft choose in C# :

DateTime aDt = DateTime.Now; 

instead of

DateTime aDt = DateTime.Now(); 

• Best practices say : Use a method when calling the member twice in succession produces different results
• And DateTime.Now is perfect example of non-determistic method/property.

Do you know if there any reason for that design ?
Or if it's just a small mistake ?

Answer 1

I believe in CLR via C#, Jeffrey Richter mentions that DateTime.Now is a mistake.

The System.DateTime class has a readonly Now property that returns the current date and time. Each time you query this property, it will return a different value. This is a mistake, and Microsoft wishes that they could fix the class by making Now a method instead of a property.

CLR via C# 3rd Edition - Page 243

Answer 2

It actually is deterministic; it's output is not random, but is based on something quite predictable.

The 'current time' changes all the time; so to be relatively "the same" with each call, that value must change so that every time it's called, it's returning the current time.

EDIT:

This just occurred to me: Of course, two subsequent calls to a property getter can return different results, if something changed the property value in the interim. Properties are not supposed to be Constants.

So, that's what happening (conceptually) with DateTime.Now; its value is being changed between subsequent calls to it.