procedure TForm.ADetailDataControllerCollapsing(  ADataController: TcxCustomDataController; ARecordIndex: Integer;  var AAllow: Boolean);var  I: Integer;  C: Integer;begin  AAllow := False;  C := 0;  for I := 0 to ADataController.RecordCount - 1 do  begin    if ADataController.GetDetailExpanding(I) then      Inc(C);    if C > 1 then      AAllow := True;  end;end;procedure TForm.ADetailDataControllerExpanding(  ADataController: TcxCustomDataController; ARecordIndex: Integer;  var AAllow: Boolean);begin  ADataController.CollapseDetails;end;procedure TForm.FormCreate(Sender: TObject);begin  inherited;  //控制只展开一个明细  cxGridVMain.DataController.OnDetailExpanding := ADetailDataControllerExpanding;  cxGridVMain.DataController.OnDetailCollapsing := ADetailDataControllerCollapsing;end;