Question

I am running into an issue with Array resizing in vb.net. I sort of understand why the issue is coming up but I’m not sure how to get around it. Basically, I have a class that has an array of objects being passed to it. I’m trying to have a sub resize the array and add another object to it. However, once it’s done, the original object does not get updated.

Optimally I would like something like this.

Sub Main()
    Dim parent As New Parent
    Dim first As New Child()
    Dim second As New Child()
    Dim children As Child() = New Child() {first, second}
    parent.children = children
    setChildren(getChildren(parent))
End Sub

Private Function getChildren(parent As Parent) As Child()
    Return parent.children
End Function

Private Sub setChildren(ByRef testArray As Child())
    testArray = New Child(3) {}
End Sub

Answer 1

Because setChildren accepts its testArray parameter by ref, it must be given a variable or field, rather than a property or function return. If Parent.children is a field, rather than a property, one could call setChildren(parent.children);. Alternatively, one could make Parent.children hold a type which itself holds a reference to an array; the two built-in types which meet that criterion would be List(Of Child) and Child()(). Incidentally, I’d suggest changing your identifier names so that type names and variable names are clearly distinct (vb.net is not case-sensitive).