In Excel VBA how to persist key variables over a 'state loss' (without writing to a cell or a file)?

Question

Excel VBA is a flexible development environment. It is pesudo-compiled. However, sometimes during development a \"state loss\" can occur. A \"state loss\" is when all var

Answer 1

One way to keep the data persistent during the lifetime of Excel is to store them on the default .Net domain attached to the instance:

Sub Usage()
    Dim dict As Object
    Set dict = GetPersistentDictionary()
End Sub

Public Function GetPersistentDictionary() As Object
    ' References:
    '  mscorlib.dll
    '  Common Language Runtime Execution Engine

    Const name = "weak-data"
    Static dict As Object

    If dict Is Nothing Then
      Dim host As New mscoree.CorRuntimeHost
      Dim domain As mscorlib.AppDomain
      host.Start
      host.GetDefaultDomain domain

      If IsObject(domain.GetData(name)) Then
        Set dict = domain.GetData(name)
      Else
        Set dict = CreateObject("Scripting.Dictionary")
        domain.SetData name, dict
      End If
    End If

    Set GetPersistentDictionary = dict
End Function