'Imports System.Reflection.Emit
 
'hier müssen alle öffentlichen members aufgeführt werden, welche die 
' schnittstelle transportieren soll.
Public Interface MyInterface
 
    'z.b. funktion
    Function Addieren() As String
 
    'z.b. property
    ReadOnly Property Datum() As Date
 
    'Sub Menuitem() 
    Function Menuitem() As Array
End Interface

'eine einfache plugin dll
Public Class myClient
    Implements [interface].MyInterface
 
    Public Function Addieren() As String Implements _
      [interface].MyInterface.Addieren
        Return "hallo"
    End Function
 
    Public ReadOnly Property Datum() As Date Implements _
      [Interface].myInterface.Datum
        Get
            Return Now
        End Get
    End Property
 
    Public Function Menuitem() As Array Implements _
      [interface].MyInterface.Menuitem
        Return New Integer() {1, 2, 3}
    End Function
 
End Class

Private Sub Button1_Click_1(sender As System.Object, e As System.EventArgs) _
  Handles Button1.Click
        Dim returnarray As String
 
        Dim MenItem As ToolStripMenuItem = CType(start.MenuStrip1.Items.Add( _
          "Plugins"), ToolStripMenuItem)
 
        returnarray = myplugin.Menuitem()
 
        MenItem.DropDownItems.Add(returnarray(0))
 
    End Sub

returnarray = myplugin.Menuitem()