Re: is null allowed in C#?

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From: Jon Skeet [C# MVP] (skeet_at_pobox.com)
Date: 08/25/04 

Date: Wed, 25 Aug 2004 07:09:02 +0100

Fei Li <FeiLi@discussions.microsoft.com> wrote:
> Is null value for a class instance allowed in C#? for example:
> MyClass obj = null;

obj is a variable, not a class instance. null is effectively something
saying, "This value isn't a reference to a class instance at all. It's
a reference to no object."
 
> If Not, how to initiate an instance with value 0?

What do you mean "with value 0"?

> How to detect if an instance is "newed" ?

If a reference is non-null, it's a reference to an instance.

> And how to pass a null value to a class constructor
> whch has a object paramer can be 0?

Just pass null.

> In general, how C# handle a pointer with value 0;

null is a special reference. You can possibly think of it as a pointer
with value 0, but it's better not to think in those terms - just think
of it as a reference meaning "No object". 

-- 
Jon Skeet - <skeet@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

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