Hide parameterless constructor on struct

Question

Is it possible to hide the parameterless constructor from a user in C#?

I want to force them to always use the constructor with parameters

e.g. this Position struct

public struct Position {     private readonly int _xposn;     private readonly int _yposn;          public int Xposn     {         get { return _xposn; }     }      public int Yposn     {         get { return _yposn; }     }      public Position(int xposn, int yposn)     {         _xposn = xposn;         _yposn = yposn;     }         } 

I only want users to be able to new up a Position by specifying the x and y coordinates.

However, the parameterless constructor is ALWAYS available.

I cannot make it private. Or even define it as public.

I have read this: Why can't I define a default constructor for a struct in .NET?

but it doesn't really help.

If this is not possible - what is the best way to detect if the Position I am being passed has values?

Explicitly checking each property field? Is there a slicker way?

Answer 1

No, you can't do this. As you said, similar question has been asked before - and I thought the answer was fairly clear that you couldn't do it.

You can create a private parameterless constructor for a struct, but not in C#. However, even if you do that it doesn't really help - because you can easily work around it:

MyStruct[] tmp = new MyStruct[1]; MyStruct gotcha = tmp[0]; 

That will be the default value of MyStruct - the "all zeroes" value - without ever calling a constructor.

You could easily add a Validate method to your struct and call that each time you received one as a parameter, admittedly.

Answer 2

Nope can't hide it. Structs cannot redefine zero arg constructor, so therefore its visibility can't be redefined.