An array of objects and calling their methods, how?!

[kaisellgren]

Hello,

Can someone help me with my issue? I've been wasting so much time on this. Basically I want to have a list of objects and I want to call some specific methods of some specific objects.

E.g.

MsgBox(Instances(0).Position(0).ToString)

It should alert a number that presents the X position, but it is not working... the box does not even appear and no errors.

This is how I create the array of objects:

Public Instances As Object()

Any ideas how to get this to work?

[Campion]

Since you have an array of Objects, you are only going to be able to pull the methods available to that object that belong to Object, which, in this case is .tostring. In order to have multiple object types in an array, and then call their methods, you will need to know what classes you are going to being throwing INTO this array, and then CType according when reading from the array.

If you are just going to put 1 object type into this array, why not use:

Dim MyArray() as ObjectType

[kaisellgren]

Hi. The object type is a custom object. Basically a new Public Class obj that I create and want to insert into the array for further use.

Public Class Test
Public TestVar As Integer = 123
End Class

Dim Instances() As Object

Instances(0) = New Test
msgbox(Instances(0).TestVar.ToString)

I need to make that to work. Got a solution for it? Do I need CType here, I am not sure how I am going to use it...

[Campion]

Okay, what you want to do is replace the word "object" with the name of your class. So, in your case, it'll look this this:

Dim Instances() as Test

Of course, Instead of an array, I would highly reccommend you use a List( of Test).

[kaisellgren]

Oh I see... well that makes sense actually, but what are the pros of using a List?

[Campion]

The main pro of using a List(of T) is that you don't have empty items, like you would an array. You can remove items, insert items, and overall have a generally better time using them. Now, I'm not saying that Arrays don't have their place, because they do, but with .NET, they simply are old, outdated, and should be used sparingly (like when splitting strings, etc.)

[kaisellgren]

MsgBox("yea")
test.Add(New testcls())
MsgBox("yea")

Whenever I run the code, I will only get "yea" popup once.. I am not sure why that code is not proper? I run this in the class:

Public test As List(Of testcls)

[Campion]

Before you use any object, you must initialize it: (The List(of T) is an object.)

Instances = new List(of test)

Dim T as new Test

Instances.Add(T)
T = nothing

Objects 101.

[kaisellgren]

Oh thanks! I was missing the keyword "New"