已经有了: TList<T>、TQueue<T>、TStack<T>、TDictionary<TKey,TValue>
为什么还有: TObjectList<T>、TObjectQueue<T>、TObjectStack<T>、TObjectDictionary<TKey,TValue> ?
还记得 Classes.TList 和 Contnrs.TObjectList 的主要区别吗?
如果元素是对象, Contnrs.TObjectList 在删除元素时会同时释放对象, 而 Classes.TList 不会.
同样在这里, Generics.Collections.TObjectList<T> 会同时释放对象, 而 Generics.Collections.TList<T> 不会.
其他也是一样.
还是要做个例子测试一下:
本例效果图:
代码文件:
为什么还有: TObjectList<T>、TObjectQueue<T>、TObjectStack<T>、TObjectDictionary<TKey,TValue> ?
还记得 Classes.TList 和 Contnrs.TObjectList 的主要区别吗?
如果元素是对象, Contnrs.TObjectList 在删除元素时会同时释放对象, 而 Classes.TList 不会.
同样在这里, Generics.Collections.TObjectList<T> 会同时释放对象, 而 Generics.Collections.TList<T> 不会.
其他也是一样.
还是要做个例子测试一下:
本例效果图:
代码文件:
unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls; type TForm1 = class(TForm) Panel1: TPanel; Panel2: TPanel; Button1: TButton; Button2: TButton; Button3: TButton; Button4: TButton; procedure FormCreate(Sender: TObject); procedure FormDestroy(Sender: TObject); procedure Button1Click(Sender: TObject); procedure Button2Click(Sender: TObject); procedure Button3Click(Sender: TObject); procedure Button4Click(Sender: TObject); end; var Form1: TForm1; implementation {$R *.dfm} uses Generics.Collections; var List : TList<TButton>; {譬如要管理 TButton 对象} ObjList : TObjectList<TButton>; procedure TForm1.FormCreate(Sender: TObject); begin List := TList<TButton>.Create; ObjList := TObjectList<TButton>.Create; Button1.Caption := '创建 Button 并添加到 TList'; Button2.Caption := '删除 TList 中的 Button'; Button3.Caption := '创建 Button 并添加到 TObjectList'; Button4.Caption := '删除 TObjectList 中的 Button'; Button2.Enabled := False; Button4.Enabled := False; end; procedure TForm1.FormDestroy(Sender: TObject); begin List.Free; ObjList.Free; end; procedure TForm1.Button1Click(Sender: TObject); var btn: TButton; begin btn := TButton.Create(Self); btn.Caption := 'TList 中的 Button'; btn.Parent := Panel1; btn.Width := 132; List.Add(btn); Button1.Enabled := False; Button2.Enabled := True; end; procedure TForm1.Button2Click(Sender: TObject); begin List.RemoveAt(0); Button1.Enabled := True; Button2.Enabled := False; end; procedure TForm1.Button3Click(Sender: TObject); var btn: TButton; begin btn := TButton.Create(Self); btn.Caption := 'TObjectList 中的 Button'; btn.Parent := Panel2; btn.Width := 132; ObjList.Add(btn); Button3.Enabled := False; Button4.Enabled := True; end; procedure TForm1.Button4Click(Sender: TObject); begin ObjList.RemoveAt(0); Button3.Enabled := True; Button4.Enabled := False; end; end.窗体文件:
object Form1: TForm1 Left = 0 Top = 0 Caption = 'Form1' ClientHeight = 153 ClientWidth = 408 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -11 Font.Name = 'Tahoma' Font.Style = [] OldCreateOrder = False OnCreate = FormCreate OnDestroy = FormDestroy PixelsPerInch = 96 TextHeight = 13 object Panel1: TPanel Left = 8 Top = 8 Width = 193 Height = 137 Caption = 'Panel1' TabOrder = 0 object Button1: TButton Left = 8 Top = 76 Width = 177 Height = 25 Caption = 'Button1' TabOrder = 0 OnClick = Button1Click end object Button2: TButton Left = 8 Top = 107 Width = 177 Height = 25 Caption = 'Button2' TabOrder = 1 OnClick = Button2Click end end object Panel2: TPanel Left = 207 Top = 8 Width = 194 Height = 137 Caption = 'Panel2' TabOrder = 1 object Button3: TButton Left = 8 Top = 76 Width = 177 Height = 25 Caption = 'Button3' TabOrder = 0 OnClick = Button3Click end object Button4: TButton Left = 8 Top = 107 Width = 177 Height = 25 Caption = 'Button4' TabOrder = 1 OnClick = Button4Click end end end