Gilbert wrote:
> H,
>
> i'm starting with asp.net/vb.net and have some questions about arrays and
> collections:
>
> 1) what's the difference between:
> dim x() as string
> and
> dim x as array

> 2) can variable 'x' in the second case contain anything (string, integer
> ... together)?

> 3) what is the correct syntax?
> dim x as arraylist
> or
> dim x as arraylist()

> 4) what to choose between:
> dim x as array (or if no difference dim x() )
> and
> dim x as arraylist

> 5) what to choose between:
> dim x as arraylist
> and
> dim x as list(of string)

> Gilbert wrote:
>> H,
>>
>> i'm starting with asp.net/vb.net and have some questions about arrays and
>> collections:
>>
>> 1) what's the difference between:
>> dim x() as string
>> and
>> dim x as array
>
> The difference is that the first one is a reference to a string array,
> while the second one is a reference to any kind of array.
>
>> 2) can variable 'x' in the second case contain anything (string, integer
>> ... together)?
>
> Yes, and no. The reference can be used for any kind of array. If you
> assign it an array of strings, you can only put strings in that array. If
> you on the other hand assigns it an array of Object, you can put anything
> in the array.
>
>> 3) what is the correct syntax?
>> dim x as arraylist
>> or
>> dim x as arraylist()
>
> That depends on what you want to do. The first one declares a reference to
> an ArrayList, the second one declares a reference to an array of ArrayList
> objects.
>
>> 4) what to choose between:
>> dim x as array (or if no difference dim x() )
>> and
>> dim x as arraylist
>
> Again, that depends on what you want to do. The first one declares a
> reference to an array (of any type). The second one declares a reference
> to an ArrayList.
>
> An ArrayList is good if you want a list that grows dynamically. An array
> can not be resized.
>
> If you are using frameword 2.0, you can use a generi list instead of an
> ArrayList (unless you want to mix data types in the list). Generics has
> made ArrayList almost obsolete.
>
>> 5) what to choose between:
>> dim x as arraylist
>> and
>> dim x as list(of string)
>
> Guess what? It depends on what you want to do. ;)
>
> An ArrayList is equivalent to a List(Of Object). If you want a list where
> you can mix data types, that is what you can use. If you only want to put
> strings in the list, you should definitely choose the second one.
>
>
> --
> Göran Andersson
> _____
> http://www.guffa.com

> The first one is the new syntax,

> Very little correction on your for the rest very fine explanation.
>
>> The first one is the new syntax,
>
> The first is a new syntax,
>
> Cor
>

> 1)dim x as string() = dim x() as string = an array of string ?
>

> 2) dim x as array() = an array of array? Is this the same as dim x( , )?
>
>

Gilbert wrote:
> Thanks for your explanation.
> If you don't mind, 2 more questions ...
>
> 1)dim x as string() = dim x() as string = an array of string ?

> 2) dim x as array() = an array of array? Is this the same as dim x( , )?

Cor Ligthert [MVP] wrote:
> Very little correction on your for the rest very fine explanation.
>
>> The first one is the new syntax,
>
> The first is a new syntax,
>
> Cor
>
>

Gilbert wrote:
> Indeed. Thanks a lot.
> And ... i swear: this is my last question:
> Look at this: the first Dim works, the second doesn't: (error)
> What do i create with the second Dim and how to use it?
>
> Dim r As Array = Array.CreateInstance(GetType(Int32), 101)
> r(0) = 3
> r(100) = 5
>
> Dim az As Array() = Array.CreateInstance(GetType(Int32), 101)
> az(0) = 3
> az(100) = 5
>

> Gilbert wrote:
>> Indeed. Thanks a lot.
>> And ... i swear: this is my last question:
>> Look at this: the first Dim works, the second doesn't: (error)
>> What do i create with the second Dim and how to use it?
>>
>> Dim r As Array = Array.CreateInstance(GetType(Int32), 101)
>> r(0) = 3
>> r(100) = 5
>>
>> Dim az As Array() = Array.CreateInstance(GetType(Int32), 101)
>> az(0) = 3
>> az(100) = 5
>>
>
> The second one declares a reference to an array of arrays, then you create
> an array of integer and try to assign it to the reference. The reference
> is for an array and the object is an array, but the data type of the
> arrays differ. Here's how you create an integer array:
>
> Dim az as Integer() = New Integer(100)
> or:
> Dim az as Integer() = Array.CreateInstance(GetType(Int32), 101)
>
> or, just for completeness, using the old syntax:
>
> Dim az() as Integer = New Integer(100)
> or:
> Dim az() as Integer = Array.CreateInstance(GetType(Int32), 101)
>
> --
> Göran Andersson
> _____
> http://www.guffa.com

> Cor Ligthert [MVP] wrote:
>> Very little correction on your for the rest very fine explanation.
>>
>>> The first one is the new syntax,
>>
>> The first is a new syntax,
>>
>> Cor
>
> I don't understand how that is a correction?
>
> You removed "one" which makes it implied, but it's still there.
>
> Then you changed "the new" to "a new", which doesn't change the meaning of
> the sentence either.
>
> So, what's the difference?
>
> --
> Göran Andersson
> _____
> http://www.guffa.com

Cor Ligthert [MVP] wrote:
> Goran,
>
> "The" new in the sentence as it is used, gives the idea that it replaces;
> "a" new means that it is an addition, very simple in my opinion. Both are
> completely valid, there is not any idea of replacing

> and there is not any
> preference for one of those, so there is not a "the" new.

>
> Cor
>
> "Göran Andersson" <guffa@guffa.com> schreef in bericht
> news:%23AETpjNWHHA.1016@TK2MSFTNGP04.phx.gbl...
>> Cor Ligthert [MVP] wrote:
>>> Very little correction on your for the rest very fine explanation.
>>>
>>>> The first one is the new syntax,
>>> The first is a new syntax,
>>>
>>> Cor
>> I don't understand how that is a correction?
>>
>> You removed "one" which makes it implied, but it's still there.
>>
>> Then you changed "the new" to "a new", which doesn't change the meaning of
>> the sentence either.
>>
>> So, what's the difference?
>>
>> --
>> Göran Andersson
>> _____
>> http://www.guffa.com
>
>

>
> Oh, yes, there is a preference. I prefer the new syntax, but that is of
> course only my own preference. :)
>