ArrayList and structures

[emc2]

Hi all,

ArrayList is a generic structure.
Let's say I have my own structure (contained of Boolean+string+int). I want to set a dynamic array based on my own structure. How....?

Thanks!

[manhit45]

Hi all,

ArrayList is a generic structure.
Let's say I have my own structure (contained of Boolean+string+int). I want to set a dynamic array based on my own structure. How....?

Thanks!

This is a example about dynamic arrray :

Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click
        Dim i As Integer
        Dim scores() As Integer

        ReDim scores(1)
        scores(0) = 100
        scores(1) = 200

        For i = 0 To scores.Length - 1
            MsgBox(scores(i))
        Next

        ReDim Preserve scores(2)

        scores(2) = 300

        For i = 0 To scores.Length - 1
            MsgBox(scores(i))
        Next
    End Sub
End Class

If you want to keep the existing items in the Array , you can use the keyword Preserve .

ReDim Preserve scores(2) :

In this case the Array dynamically allocate one more String value and keep the existing values.

[jmcilhinney]

When you say "generic" don't mean it in the .NET sense, because an ArrayList is not a generic class, which is the problem. From .NET 2.0 onwards you should not use an ArrayList at all but rather use the List(Of T), which is a generic class. If you have your own type named SomeType, you would create a List(Of SomeType). The collection will then only accept SomeType objects and it will return its items as SomeType values rather than Object references.

[emc2]

Thanks. That's what I meant.
Can you write the releavnt syntax?

[emc2]

Thanks, but I woudln't prefer the "redim" statement. It's a VB6 .

This is a example about dynamic arrray :

Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click
        Dim i As Integer
        Dim scores() As Integer

        ReDim scores(1)
        scores(0) = 100
        scores(1) = 200

        For i = 0 To scores.Length - 1
            MsgBox(scores(i))
        Next

        ReDim Preserve scores(2)

        scores(2) = 300

        For i = 0 To scores.Length - 1
            MsgBox(scores(i))
        Next
    End Sub
End Class

If you want to keep the existing items in the Array , you can use the keyword Preserve .

ReDim Preserve scores(2) :

In this case the Array dynamically allocate one more String value and keep the existing values.

[chris128]

You dont need to do all that though, as JMC has explained you can just use the generic List(Of T) like so:

Dim MyCustomTypeList As New List(Of MyCustomStructure)
 
Dim structureinstance As New MyCustomStructure
structureinstance.SomeStringProperty = "a string"
'etc etc
 
MyCustomTypeList.Add(structureinstance)

Get the idea?

EDIT: When you say "its a VB6"... do you mean your application is written in VB6? If so, you should post it in the VB6 forum and not the VB.NET forum

[Shaggy Hiker]

VB6 wouldn't have the ArrayList, so the interpretation of Redim being VB6 is that it is legacy.

[chris128]

Ah, thats what I was hoping thanks for the clarification

[emc2]

That's exactly what I meant :-)
Thanks you all!

[chris128]

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