form runtime error

[awake2424]

 Private Sub Form_Open(Cancel As Integer)
Me.TAT = WorkingDays(Due_Date, Result_Date)
End Sub

When I open the form I get a You can't assign a value to this object.

I have a function, that excludes weekends and holidays from a calculation. Thanks .

VB

 Option Compare Database
Option Explicit

Public Function WorkingDays(Due_Date As Date, Result_Date As Date) As Integer
'-- Return the number of WorkingDays between Due_Date and Result_Date
On Error GoTo err_workingDays

Dim intCount As Integer

If IsDate(Due_Date) And IsDate(Result_Date) Then
   If Result_Date >= Due_Date Then
 
      intCount = 0
      Do While Due_Date < Result_Date
         Due_Date = Due_Date + 1
     '-- Holiday code
           If Weekday(Due_Date, vbMonday) <= 5 And _
           IsNull(DLookup("[Description]", "Holidays", _
            "[Holiday] = " & Format(Due_Date, "\#mm\/dd\/yyyy\#;;;\N\u\l\l"))) Then: intCount = intCount + 1
      Loop
 
      WorkingDays = intCount
      Else
          WorkingDays = -1  '-- To show an error
 
   End If
 
   Else
      WorkingDays = -1  '-- To show an error
End If
exit_workingDays:
   Exit Function

err_workingDays:
   MsgBox "Error No:    " & Err.Number & vbCr & _
   "Description: " & Err.Description
   Resume exit_workingDays

End Function

 

[awake2424]

Resolved by changing to:

 Private Sub Form_Load()
    Me.TAT = WorkingDays(Due_Date, Result_Date)
End Sub

not all the records seem to update, but this seemed to work. Thanks.