VBA Excel Run-time error Automation error

Question

I had a Run-time error

'-2147418105 (800100007)': Automation error The object invoked has disconnected from its clients.

which is raised once in a while. I can't relate it to a specific context for this error. The only clue I have is that before using ADO code I never had that error. The implemented pattern was used many times.

I use Excel 2016 32 bits on windows 7 with a vba code.

Private mForm As frmCfgPrjctTm
Public Sub U_CfgPrjctTm_OnOpen()
    If (mForm Is Nothing) Then
        Call U_UnlockTeam
        Set mForm = New frmCfgPrjctTm
    End If
    '>>>>>> the error occurs after this comment
    mForm.Show vbModeless
End Sub

The code to "close" the form is as following

Public Sub U_CfgPrjctTm_OnClose()
    If (Not mForm Is Nothing) Then
        mForm.Hide
        Dim tmp As frmCfgPrjctTm
        Set tmp = mForm
        Set mForm = Nothing
        Unload tmp
    End If
End Sub

and in the form code (childCfgPrjctTmSettings and childCfgPrjctTmSettings are defined in an enum to falg a user action before closing the form)

Private Sub UserForm_QueryClose(Cancel As Integer, CloseMode As Integer)
    Call U_UnlockTeam
    Select Case CloseMode
        Case vbAppWindows, vbAppTaskManager
            Call U_CfgPrjctTm_OnClose
        Case vbFormControlMenu, vbFormCode
            Call Save
            Select Case mbOpenForm
                Case childCfgPrjctTmSettings
                    ' this opens another form
                    Call U_Sttngs_OnOpen(delUsr)
                Case childCfgPrjctTmUsrId
                    ' this opens another form
                    Call U_UsrLggd_OnOpen(dpyUsrLggdCfgPrjctTeam)
            End Select
    End Select
    Cancel = False
End Sub

and in the form code

Private Sub UserForm_QueryClose(Cancel As Integer, CloseMode As Integer)
Call U_UnlockTeam
Select Case CloseMode
    Case vbAppWindows, vbAppTaskManager
        Call U_CfgPrjctTm_OnClose
    Case vbFormControlMenu, vbFormCode
        Call Save
        Select Case mbOpenForm
            Case childCfgPrjctTmSettings

                Call U_Sttngs_OnOpen(delUsr)
            Case childCfgPrjctTmUsrId
                Call U_UsrLggd_OnOpen(dpyUsrLggdCfgPrjctTeam)
        End Select
End Select
Cancel = False

End Sub

This error is raised after creating a form and at the very moment to show it up. The call U_UnlockTeam involves some ADO code called inside to retreive data from a data base. The form has no Activate event handler. Did some one have the same issue and how did you cope with ?

Answer 1

I am able to reproduce the error. The issue is that you unload the form inside the form. Take just an empty userform and the following code in a module. Run the code and close the form by clicking on X. There should be no code behind the form! If you run the code a second time you will get the error mentioned.

Option Explicit

Private mForm As UserForm1
Public Sub U_CfgPrjctTm_OnOpen()
    If mForm Is Nothing Then
        'Call U_UnlockTeam
        Set mForm = New UserForm1
    End If
    '>>>>>> the error occurs after this comment
    mForm.Show vbModeless
End Sub

Reason of the behavior is that the class destroyed itself and mForm is a module wide variable which does not know it was destroyed when calling the code the second time.

Solution would be to avoid a self-destroing class/userform or as a workaround make mForm a local variable.

Here is a better explanation https://excelmacromastery.com/vba-user-forms-1/#Cancelling_the_UserForm