Delphi 2009 泛型容器单元(Generics.Collections)[1]: TList<T>

Delphi 2009 新增了泛型容器单元: Generics.Collections, 同时还有一个 Generics.Defaults 单元做支持.

Generics.Collections 包含了以下实用类:
TList<T>
TQueue<T>
TStack<T>
TDictionary<TKey,TValue>
TObjectList<T>
TObjectQueue<T>
TObjectStack<T>
TObjectDictionary<TKey,TValue>

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有了以上泛型的容器, 恐怕 Classes.TList 和 Contnrs 单元下的 TObjectList 等系列容器也就只为兼容存在了.

Generics.Collections.TList<T> 既然是泛型的, 那肯定应该容得下字符串列表, 本例就依此测试吧.

如果你对泛型不了解, 应先看看: http://www.cnblogs.com/del/archive/2008/08/14/1268258.html

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本例效果图:

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代码文件:

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unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    Edit1: TEdit;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    Button6: TButton;
    Button7: TButton;
    Button8: TButton;
    Button9: TButton;
    Button10: TButton;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure Edit1Change(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
    procedure Button6Click(Sender: TObject);
    procedure Button7Click(Sender: TObject);
    procedure Button8Click(Sender: TObject);
    procedure Button9Click(Sender: TObject);
    procedure Button10Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses Generics.Collections; {Delphi 2009 新增的泛型容器单元}

var
  List: TList<string>;  {定义一个泛型 TList 类, 这指定了要用于 string}
  str: string = 'Test';

{建立}
procedure TForm1.FormCreate(Sender: TObject);
begin
  List := TList<string>.Create;

  Memo1.Clear;
  Edit1.Text := str;
  Button1.Caption := Button1.Caption + ' 显示';
  Button2.Caption := Button2.Caption + ' 添加';
  Button3.Caption := Button3.Caption + ' 插入';
  Button4.Caption := Button4.Caption + ' 删除1';
  Button5.Caption := Button5.Caption + ' 删除2';
  Button6.Caption := Button6.Caption + ' 查找';
  Button7.Caption := Button7.Caption + ' 排序';
  Button8.Caption := Button8.Caption + ' 翻转';
  Button9.Caption := Button9.Caption + ' 清空';
  Button10.Caption := Button10.Caption + ' 添加数组';
end;

{释放}
procedure TForm1.FormDestroy(Sender: TObject);
begin
  List.Free;
end;

procedure TForm1.Edit1Change(Sender: TObject);
begin
  if Edit1.Text <> '' then str := Edit1.Text;
end;

{显示}
procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
begin
  Memo1.Clear;
  for i := 0 to List.Count - 1 do
    Memo1.Lines.Add(List[i]);  {List[i] = List.Item[i]}
  Text := Format('当前总数: %d', [List.Count]);
end;

{添加}
procedure TForm1.Button2Click(Sender: TObject);
begin
  List.Add(str);
  Button1.Click; {刷新显示}
end;

{插入, 譬如插入在最前面}
procedure TForm1.Button3Click(Sender: TObject);
begin
  List.Insert(0, str);
  Button1.Click;
end;

{根据序号删除, 譬如删除第一个数据}
procedure TForm1.Button4Click(Sender: TObject);
begin
  List.RemoveAt(0);
  Button1.Click;
end;

{根据内容删除, 譬如删除第一个数据}
procedure TForm1.Button5Click(Sender: TObject);
var
  s: string;
begin
  s := List[0];
  List.Remove(s);
  Button1.Click;
end;

{查找}
procedure TForm1.Button6Click(Sender: TObject);
var
  n: Integer;
begin
  n := List.IndexOf(str); {LastIndexOf 是从后面找; 也可用 List.Contains(str) 判断是否包含 str}
  if n = -1 then
    ShowMessage('没找到')
  else
    ShowMessageFmt('%s 是第 %d 个', [str, n+1]);
end;

{排序}
procedure TForm1.Button7Click(Sender: TObject);
begin
  List.Sort;
  Button1.Click;
end;

{翻转}
procedure TForm1.Button8Click(Sender: TObject);
begin
  List.Reverse;
  Button1.Click;
end;

{清空}
procedure TForm1.Button9Click(Sender: TObject);
begin
  List.Clear;
  Button1.Click;
end;

{添加数组}
procedure TForm1.Button10Click(Sender: TObject);
const
  arr: array[0..2] of string = ('CodeGear', 'Delphi', '2009');
begin
  List.Add('Embarcadero');
  List.AddRange(arr);
  Button1.Click;
end;

end.

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窗体文件:

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object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 201
  ClientWidth = 349
  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 Memo1: TMemo
    Left = 0
    Top = 0
    Width = 121
    Height = 201
    Align = alLeft
    Lines.Strings = (
      'Memo1')
    ScrollBars = ssBoth
    TabOrder = 0
    ExplicitHeight = 206
  end
  object Button1: TButton
    Left = 136
    Top = 13
    Width = 81
    Height = 25
    Caption = 'Button1'
    TabOrder = 1
    OnClick = Button1Click
  end
  object Button2: TButton
    Left = 127
    Top = 44
    Width = 100
    Height = 25
    Caption = 'Button2'
    TabOrder = 2
    OnClick = Button2Click
  end
  object Button3: TButton
    Left = 127
    Top = 75
    Width = 100
    Height = 25
    Caption = 'Button3'
    TabOrder = 3
    OnClick = Button3Click
  end
  object Button4: TButton
    Left = 127
    Top = 106
    Width = 100
    Height = 25
    Caption = 'Button4'
    TabOrder = 4
    OnClick = Button4Click
  end
  object Button5: TButton
    Left = 127
    Top = 137
    Width = 100
    Height = 25
    Caption = 'Button5'
    TabOrder = 5
    OnClick = Button5Click
  end
  object Button6: TButton
    Left = 240
    Top = 44
    Width = 100
    Height = 25
    Caption = 'Button6'
    TabOrder = 6
    OnClick = Button6Click
  end
  object Button7: TButton
    Left = 240
    Top = 75
    Width = 100
    Height = 25
    Caption = 'Button7'
    TabOrder = 7
    OnClick = Button7Click
  end
  object Button8: TButton
    Left = 240
    Top = 106
    Width = 100
    Height = 25
    Caption = 'Button8'
    TabOrder = 8
    OnClick = Button8Click
  end
  object Button9: TButton
    Left = 240
    Top = 137
    Width = 100
    Height = 25
    Caption = 'Button9'
    TabOrder = 9
    OnClick = Button9Click
  end
  object Edit1: TEdit
    Left = 240
    Top = 15
    Width = 100
    Height = 21
    TabOrder = 10
    Text = 'Edit1'
    OnChange = Edit1Change
  end
  object Button10: TButton
    Left = 127
    Top = 168
    Width = 214
    Height = 25
    Caption = 'Button10'
    TabOrder = 11
    OnClick = Button10Click
  end
end