Dynamic Arrays

[Larry Charlton]

Is there a high performance way in .Net to dynamically build single dimension
arrays when the number of elements in the array is unknown until after the
array is built? (i.e. I only need the array to grow, I don't need to remove
elements)

I noticed that Dim myVar As List(of X) gets converted to Dim myVar() As X
when returned from a web service. I'd like to build a single code base that
supports either using web services (Tiers) or tightly linked assemblies
(Layers). It would appear for that to work I'll need to use Arrays instead
of the new generics.

Thanks,

Larry

[Peter Bromberg [C# MVP]]

Larry,
No, there isn't. An array, once created, has a fixed upperBound. You can use
the ArrayList class as an alternative.
Peter

--
Co-founder, Eggheadcafe.com developer portal:
http://www.eggheadcafe.com
UnBlog:
http://petesbloggerama.blogspot.com


"Larry Charlton" wrote:

Is there a high performance way in .Net to dynamically build single dimension
arrays when the number of elements in the array is unknown until after the
array is built? (i.e. I only need the array to grow, I don't need to remove
elements)

I noticed that Dim myVar As List(of X) gets converted to Dim myVar() As X
when returned from a web service. I'd like to build a single code base that
supports either using web services (Tiers) or tightly linked assemblies
(Layers). It would appear for that to work I'll need to use Arrays instead
of the new generics.

Thanks,

Larry

[bruce barker \(sqlwork.com\)]

the array list uses an array under the covers (just keeps copying to new
bigger ones as items are added), so you want to give it a good hint on the
initial size.

-- bruce (sqlwork.com)

"Peter Bromberg [C# MVP]" <pb*******@yahoo.nospammin.com> wrote in message
news:94**********************************@microsof t.com...

Larry,
No, there isn't. An array, once created, has a fixed upperBound. You can
use
the ArrayList class as an alternative.
Peter

--
Co-founder, Eggheadcafe.com developer portal:
http://www.eggheadcafe.com
UnBlog:
http://petesbloggerama.blogspot.com


"Larry Charlton" wrote:

Is there a high performance way in .Net to dynamically build single
dimension
arrays when the number of elements in the array is unknown until after
the
array is built? (i.e. I only need the array to grow, I don't need to
remove
elements)

I noticed that Dim myVar As List(of X) gets converted to Dim myVar() As X
when returned from a web service. I'd like to build a single code base
that
supports either using web services (Tiers) or tightly linked assemblies
(Layers). It would appear for that to work I'll need to use Arrays
instead
of the new generics.

Thanks,

Larry

[PeterKellner]

On Mon, 5 Jun 2006 11:52:01 -0700, Larry Charlton
<La***********@discussions.microsoft.com> wrote:

Is there a high performance way in .Net to dynamically build single dimension
arrays when the number of elements in the array is unknown until after the
array is built? (i.e. I only need the array to grow, I don't need to remove
elements)

I noticed that Dim myVar As List(of X) gets converted to Dim myVar() As X
when returned from a web service. I'd like to build a single code base that
supports either using web services (Tiers) or tightly linked assemblies
(Layers). It would appear for that to work I'll need to use Arrays instead
of the new generics.

Thanks,

Larry

If you are looking for high performance, you should switch to a
generic List.

List<int> myList = new List<int>();
myList.Add(1);
myList.Add(2);
etc.

When 2.0 came out, I switched from an ArrayList to a Generic List and
saw a 15x improvement in speed. (of course, mileage my vary...)

The reason is because generic's create native types for the CLR to
process. ArrayList's have to box and unbox on every reference. Ouch.

Good luck.
Peter Kellner
http://peterkellner.net

[David Anton]

As Peter B. and Peter K. pointed out, an ArrayList or a generic List are
probably better, but be aware that you can resize arrays in .NET.
In .NET 2, you can use Array.Resize to resize single dimension arrays. Be
aware that it does copy the contents to a new array internally on each
'Resize' call. This is the main reason why the alternatives mentioned are
faster.
For multi-dimensional arrays, you can use the approach I discuss here:
http://www.tangiblesoftwaresolutions...20Preserve.htm
--
David Anton
www.tangiblesoftwaresolutions.com
Instant C#: VB to C# converter
Instant VB: C# to VB converter
Instant C++: C# to C++ converter & VB to C++ converter
Instant J#: VB to J# converter

"Larry Charlton" wrote:

Is there a high performance way in .Net to dynamically build single dimension
arrays when the number of elements in the array is unknown until after the
array is built? (i.e. I only need the array to grow, I don't need to remove
elements)

I noticed that Dim myVar As List(of X) gets converted to Dim myVar() As X
when returned from a web service. I'd like to build a single code base that
supports either using web services (Tiers) or tightly linked assemblies
(Layers). It would appear for that to work I'll need to use Arrays instead
of the new generics.

Thanks,

Larry