Developing a COM Class Collection in VB.NET without using the COM Template

you can find the code here

This is an example of a COM Class Collection written in VB.NET.

You need to start a new project of type library, and set the project property Build -> Register for COM Interop
Do not check: Application, Assembly Information, Make Class COM Visible.
We are using the COMVisible attribute to decide which class is visible for us
The class will have both a default property  and an iterator. The iterator is exposed defining a public function.

Function GetEnumerator() as IEnumerator
End Function


It is also a Good Idea having the class to implement IEnumerable

Function GetEnumerator() as IEnumerator Implements IEnumerable.GetEnumerator

End Function

In order to get the new GUID use can either use the VB.NET COM template of the Tools- Create GUID tool.
In addtion you can also use my C# Com template to start with, and translate the code with a C# to VB.NET tool.
Other wise, you can just use the VB.NET COM tool. It is kind of easy to use and much faster

Imports System.Runtime.InteropServices
Imports System.Collections

'Wee first define the interface of the Collection
<Guid("8beb176f-5357-4bb9-a5c1-38bdd0f7d3df"), _
InterfaceType(ComInterfaceType.InterfaceIsDual), _
ComVisible(True)> _
Public Interface INewEmployees
    Inherits System.Collections.IEnumerable


    <DispId(-4)> Shadows Function GetEnumerator() As IEnumerator 'Iterator
    <DispId(1)> Sub Add(ByVal key As Object, ByVal value As Object)
    <DispId(2)> ReadOnly Property Count()
    <DispId(3)> Sub Remove(ByVal key As Object)
    <DispId(0)> Default Property Item(ByVal key As Object)

End Interface

'We define the event interface
<Guid("e96bda2f-596f-419b-840c-4bd165930c4d"), _
InterfaceType(ComInterfaceType.InterfaceIsIDispatch), _
ComVisible(True)> _
Public Interface INewEmployeesEvents

End Interface



'<ComClass(NewEmployees.ClassId, NewEmployees.InterfaceId, NewEmployees.EventsId)> _
<Guid("67d85fea-43d6-457e-8db1-cc9601bdd9ec"), _
ClassInterface(ClassInterfaceType.None), _
ComSourceInterfaces(GetType(INewEmployeesEvents)), _
ComDefaultInterface(GetType(INewEmployees)), _
ComVisible(True)> _
Public Class NewEmployees
    Implements INewEmployees


#Region "COM GUIDs"
    ' These  GUIDs provide the COM identity for this class 
    ' and its COM interfaces. If you change them, existing 
    ' clients will no longer be able to access the class.
    Public Const ClassId As String = "67d85fea-43d6-457e-8db1-cc9601bdd9ec"
    Public Const InterfaceId As String = "8beb176f-5357-4bb9-a5c1-38bdd0f7d3df"
    Public Const EventsId As String = "e96bda2f-596f-419b-840c-4bd165930c4d"
#End Region

    ' A creatable COM class must have a Public Sub New() 
    ' with no parameters, otherwise, the class will not be 
    ' registered in the COM registry and cannot be created 
    ' via CreateObject.
    Dim _SortedList As SortedList
    Public Sub New()
        MyBase.New()
        _SortedList = New SortedList
    End Sub



    Default Public Property Item(ByVal key As Object) Implements INewEmployees.Item
        Get
            Return _SortedList(key)
        End Get
        Set(ByVal value)
            _SortedList(key) = value

        End Set
    End Property

    Public ReadOnly Property Count() Implements INewEmployees.Count
        Get
            Return _SortedList.Count
        End Get
    End Property


    Public Sub Remove(ByVal key As Object) Implements INewEmployees.Remove
        _SortedList.Remove(key)
    End Sub


    Public Sub Add(ByVal key As Object, ByVal value As Object) Implements INewEmployees.Add
        _SortedList.Add(key, value)
    End Sub


    Public Function GetEnumerator() As System.Collections.IEnumerator Implements INewEmployees.GetEnumerator, System.Collections.IEnumerable.GetEnumerator
        'Return _SortedList.GetEnumerator()
        Dim keys As ICollection = _SortedList.Keys
        Return CType(keys.GetEnumerator, IEnumerator)
    End Function


End Class