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>
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:
本例效果图:
代码文件:
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.
