Here is another way if you want the order of layout tabs are
<CommandMethod("LayoutTabList")> _
Public Sub LayoutTabList()
Dim doc As Document = Application.DocumentManager.MdiActiveDocument
Dim db As Database = doc.Database
Dim ed As Editor = doc.Editor
Dim layAndTab As SortedDictionary(Of Integer, String) = New SortedDictionary(Of Integer, String)
Using trx As Transaction = db.TransactionManager.StartTransaction()
Dim layDict As DBDictionary = db.LayoutDictionaryId.GetObject(OpenMode.ForRead)
For Each entry As DBDictionaryEntry In layDict
Dim lay As Layout = CType(entry.Value.GetObject(OpenMode.ForRead), Layout)
layAndTab.Add(lay.TabOrder, lay.LayoutName)
Next
trx.Commit()
End Using
For Each v In layAndTab.Values
ed.WriteMessage(v & vbCrLf)
Next
End Sub