ArrayList inside Structure/Class

[sage]

Is it not possible to use an ArrayList inside of a Structure or a Class?

I keep getting 'Object reference not set to instance of an object'

I am using New.

i.e.

Stucture ABC
Dim al as ArrayList
End Structure


Private Sub X()

Dim Struct1 as New ABC

Struct1.al.Add("anything")

End Sub

[grilkip]

It's because the arraylist hasn't been instanciated yet.

I'm not a 100% sure if you can do this inside a Structure, if not then use a Class instead.

Structure ABC
    Public al as ArrayList = New ArrayList
End Structure

or

Structure ABC
    Public al as ArrayList
 
    Public Sub New()
        al = New ArrayList
    End Sub
End Structure

[sage]

Your first solution works for a class. Thanks grillkip.