Why not to change the datatype of standard procedures

[Knut Ole]

I have a form, Query18, in which I have these comboboxes... thing is, I have had it working fine for long, then suddenly! I get this errors... (for all comboboxes, basically all the code i'd put so far in the form...)

there are no superfluent subs or ifs... when i access the vba from the control property event handler, i am brought correctly to the right code-piece. when it's run, however, i get the error...

i so hope this is not a bug!? any help greatly appreciated! thank you..

Option Compare Database
 
Private Sub Combo333_BeforeUpdate(Cancel As Integer)
 
End Sub
 
Private Sub Combo336_KeyDown(KeyCode As Integer, Shift As Integer)
'Form_Query18.Combo336.Dropdown
End Sub
 
Private Sub Combo336_NotInList(NewData As String, Response As Integer)
 
Dim strMsg As String
Dim MyDB As DAO.Database
Dim rstNewContact As DAO.Recordset
 
strMsg = "'" & NewData & "' is not in the list.  "
strMsg = strMsg & "Would you like to add a New Customer?"
 
If vbNo = MsgBox(strMsg, vbYesNo + vbQuestion, "New Customer") Then
  Response = acDataErrDisplay 'Access displays its standard Error Message
Else
  'Decided to Add the New Customer
  Set MyDB = CurrentDb
  Set rstNewContact = MyDB.OpenRecordset("Contacts", dbOpenDynaset)
    rstNewContact.AddNew
      rstNewContact("LastName") = NewData
    rstNewContact.Update
 
    Response = acDataErrAdded   'Item added to underlying Recordset and the Combo
                                'Box is Requeried, Item added to List
    rstNewContact.Close
    Set rstNewContact = Nothing
End If
bolNewRec = True
 
End Sub
 
Private Sub Combo340_KeyDown(KeyCode As Integer, Shift As Integer)
If bolNewRec = True Then
    Form_Query18.Combo340.AutoExpand = False
 
Else
    Form_Query18.Combo340.Dropdown
End If
End Sub
 
Private Sub Combo340_NotInList(NewData As String, Response As Integer)
 
Dim strMsg As String
Dim MyDB As DAO.Database
Dim rstNewContact As DAO.Recordset
 
strMsg = "'" & NewData & "' is not in the list.  "
strMsg = strMsg & "Would you like to add a New Customer?"
 
If vbNo = MsgBox(strMsg, vbYesNo + vbQuestion, "New Customer") Then
  Response = acDataErrDisplay 'Access displays its standard Error Message
Else
  'Decided to Add the New Customer
  Set MyDB = CurrentDb
  Set rstNewContact = MyDB.OpenRecordset("Contacts", dbOpenDynaset)
    rstNewContact.MoveLast
    rstNewContact.Edit
    rstNewContact("FirstName") = NewData
    rstNewContact.Update
 
    Response = acDataErrAdded   'Item added to underlying Recordset and the Combo
                                'Box is Requeried, Item added to List
    rstNewContact.Close
    Set rstNewContact = Nothing
End If
 
    Response = acDataErrAdded
End Sub
 
Private Sub Mobile_KeyDown(KeyCode As Integer, Shift As Integer)
If bolNewRec = True Then
    Form_Query18.Mobile.AutoExpand = False
 
Else
    Form_Query18.Mobile.Dropdown
End If
End Sub
 
Private Sub Mobile_NotInList(NewData As Integer, Response As Integer)
Dim strMsg As String
Dim MyDB As DAO.Database
Dim rstNewContact As DAO.Recordset
 
strMsg = "'" & NewData & "' is not in the list.  "
strMsg = strMsg & "Would you like to add a New Customer?"
 
If vbNo = MsgBox(strMsg, vbYesNo + vbQuestion, "New Customer") Then
  Response = acDataErrDisplay 'Access displays its standard Error Message
Else
  'Decided to Add the New Customer
  Set MyDB = CurrentDb
  Set rstNewContact = MyDB.OpenRecordset("Contacts", dbOpenDynaset)
    rstNewContact.MoveLast
    rstNewContact.Edit
    rstNewContact("Mobile") = NewData
    rstNewContact.Update
 
    Response = acDataErrAdded   'Item added to underlying Recordset and the Combo
                                'Box is Requeried, Item added to List
    rstNewContact.Close
    Set rstNewContact = Nothing
End If
 
    Response = acDataErrAdded
End Sub
 

[Knut Ole]

weird how the solution appears when you least expect it...
for my part, i had changed the data type of one of the parameters for NotInList on line 86.. NewData as Integer instead of String (as my input table field in that combobox is an integer, and i got a previous data type mismatch for it..)

so changing one datatype messed up the whole code. good to know.

[TheSmileyCoder]

You cannot (to my knowledge) change the datatypes of standard built-in procedures.

Think of it this way. Access has programmed actions to do, when you type in something that is "NotInList". At some point in the execution of that native access code, it will call or include your custom code. From the nature of the declaration alone, you can see that access has certain expectations from the code.

Private Sub Combo336_NotInList(NewData As String, Response As Integer)

Even though NotInList is not a function, it does in fact return variables, for instance the Response. Whatever you do with Response will be passed back to the calling procedure, so that access knows how to proceed. If you change the datatype, there will be a datatype mismatch (Access passed you an integer, and was built to expect an integer, but you've changed the program to expect a string or vice versa)

I hope that cleared it up a bit, and didn't just add to the confusion :P