The InitializeComboBox event is fired when a field is defined as a combo box that is filled by script. In this event all possible combinations for the value / description pairs must be created as separated string of all items so that the for an existing value needed description is available for displaying. This event can be omitted for scripted combo boxes not using descriptions.

ValidationForm_InitializeComboBox( _
    ByVal FieldName As String, _
    ByRef ComboboxItems As String _
    )

FieldName

Name of the field that is defined as a combo box.

ComboboxItems

String containing a separated list of the items displayed in the combo box. By default a semicolon is used as separator for values, a pipe as separator for descriptions, different separators can be configured in the validation form layout designer.

' Class Script 
Private Sub ValidationForm_InitializeComboBox(ByVal FieldName As String, ByRef ComboboxItems As String) 
   Select Case FieldName
      Case "DocInfo"
         ComboboxItems = _
              "Order|1;" & _
              "Invoice|2;" & _
              "Delivery Note|3;" & _
              "Credit|4"
   End Select
End Sub