Visual Basic

Public Class LinerTypesCollection
        Inherits System.Collections.ObjectModel.ObservableCollection(Of String)

        Public Sub New(ByVal IsMetric As Boolean)

           ' Do stuff
           
        End Sub
   End Class

Namespace Base.Controls.Panels
    Partial Public Class StartPanel
        Public Sub New (ByVal bool as Boolean, Optional ByVal bool2 as Boolean = false)

            ' This works.
            cmbBox.ItemsSource = New LinerTypesCollection(False)
        End Sub
    End Class
End Namespace

Namespace Base.Utilities
    Public Class ConnectionOption
        Public Sub New (ByVal IsMetric as Boolean)

            ' This does not work. I cannot get IntelliSense to acknowledge that LinerTypesCollection exists.
            cmbBox.ItemsSource = New LinerTypesCollection(False)
        End Sub
    End Class
End Namespace