Private Sub cboPubName_AfterUpdate()
    Dim strSQL As String
    mstrPubName = cboPubName.Text

' Develop SQL statement for row source of Project Number combo box:
    strSQL = "SELECT DISTINCTROW [tblAssignment].[ProjectNumber] FROM tblAssignment WHERE " & _
        "[tblAssignment].[PubName] = '" & mstrPubName & "';"

' Finish establishing combo box properties:
    cboProjNum.RowSource = strSQL
    cboProjNum.RowSourceType = "Table/Query"
    cboProjNum.BoundColumn = 1

End Sub