Как работать с коллекциями в структуре

    Structure struct
 
        Public _coll As Collection
 
    End Structure
 
    Private Sub sub1()
 
        Dim s As String = "bla bla bla"
 
        Dim str As New struct
 
        str._coll.Add(s)
 
    End Sub

Structure struct
        Public _coll As Collection
    End Structure
    Dim str As New struct
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim s As String = "bla bla bla"
        str._coll = New Collection
        str._coll.Add(s)
    End Sub
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        MsgBox(str._coll.Count & vbCrLf & str._coll.Item(1).ToString)
    End Sub

sub create() 
_coll=new collection 
End Sub

Class blabla 
Private str as struct
Sub new () 
Str.create
End sub
End class