Why does string not require a new like other reference types?

[Ray Cassick]

I can't believe why I had not noticed this before and why I never asked it
before...

When defining a string why is it not required to use the new keyword? Like:

Dim a As String = New String

You can do it when using the string type with some arguments in the
constructor but it look like there is no empty constructor on the String
class.

Seem odd to me that all the other reference types seem to require a new to
create the instance portion of the type and String does not.

Thanks for any insight...

[Ray Cassick]

I am asking because I wanted to explain the difference between these two
types to someone else and could not come up with a real reason (other than -
it just works that way with strings) for them. Right, I'm not the designer
but that does not stop me form being curious :)

Inconsistencies bug me. It just seemed like something that would pop up in a
Microsoft document somewhere and I have had no luck in locating it. Another
thing that bugs me.

Now that I had the discussion I am ok. Seems more like it was a mixture of
how strings are inherently immutable and how it better to make them work
like ValueTypes in these cases.
"Cor Ligthert[MVP]" <no************ @planet.nlwrote in message
news:1A******** *************** ***********@mic rosoft.com...

Ray,

Your replies sounds to me like somebody driving a car once heard that
there was a carburator in it, and now ask why he cannot find it in his
current car.

It is important for a driver, that a car do exactly as it should do? You
are not the one who designs Net and the way it works.

By the way, playing with words does not work here.

Dim a as integer "results" in a 0
Dim b as string "results" in a ""

Both as with all valuetypes with the lowest value possible.

Strange that you did not mention the Struct DateTime which has almost the
same behaviours

Just my idea reading your replies.

[J.B. Moreno]

In article <e1************ **@TK2MSFTNGP05 .phx.gbl>,
Ray Cassick <rc******@enter procity.comwrot e:

The storage is declared on the managed stack. IF the type is a ValueType
then nothing else is needed and the storage is all done on the stack. IF the
type is a reference type then the stack storage ends up just being a pointer
that will end up being an address on the heap somewhere but points to
nowhere just yet.

Pretty much, there are exceptions...

When you do this:

Dim a As ClassName = New ClassName...

THEN the storage is allocated on the stack AND the storage is allocated on
the heap and the stack points to the proper location on the heap.

So, I guess my question is.. if String is a reference type why do you NOT
NEED to allocate it using the New keyword every time? Almost seems like
strings are an odd case with respect to this.

Nope.

This is one of the exceptions to the stack/heap storage option. String
constants results in a reference that points to the code. Just as you'd
do if you were programming in assembly and were assigning a pointer to
a string constant.

So, string constants are pointers to code, and the implementation of
the + and & operators create a new reference and then return that.

--
J.B. Moreno