Code:
Object oPessoadbComboForm is a dbComboForm
    Entry_Item ARQUIVO.PESSOA

    Set Location                 to 140 70
    Set Size                     to 12 60
    Set Label                    to "Pessoa:"
    Set Label_Col_Offset         to 2
    Set Label_Justification_Mode to JMode_Right
    Set Entry_State              to False

    Procedure OnChange
        Integer iPessoa
        
        Forward Send OnChange
        
        Get Field_Current_Value of (Server(Self)) Field ARQUIVO.PESSOA to iPessoa
        
        Set Form_Mask of (oCpfCnpjdbForm(Self)) to (If (iPessoa=C_PessoaJuridica,'##.###.###/####-##','###.###.###-##'))
    End_Procedure // OnChange
End_Object // oPessoadbComboForm