var  rec: Integer = 0;  //记录增行按钮点击次数implementation{$R *.dfm}//动态释放单个组件内存，即销毁组件procedure TForm1.DeleteRow(Sender: TObject);begin  if rec < 1 then    Exit  else  begin    TPanel(Panel1.Controls[rec]).Free;  //释放单个控件内存    TComboBox(Panel2.Controls[rec]).Free;    TEdit(Panel3.Controls[rec]).Free;    Dec(rec);  //增行按钮次数递减  end;end;//动态创建单个组件procedure TForm1.AddRow(Sender: TObject);  var  e:Integer;  //记录当前组件总数量  edt: TEdit;  pnl: TPanel;  combo: TComboBox;begin  Inc(rec);  //按钮点击次数  e := Panel3.ControlCount;   //edit数量  //动态创建Edit  edt := TEdit.Create(Panel3);   edt.Parent := Panel3;  edt.Left := Edit1.Left;  edt.Top := Edit1.Top + (Edit1.Height + 3)*e;  edt.Width :=Edit1.Width;  edt.Height := Edit1.Height;  edt.Text := ‘Edit‘ + IntToStr(rec + 1);  edt.Show;  //Panel、ComboBox创建方法与Edit相同 end;