二十五、详测 Generics Collections TDictionary(1): Add、Items、Keys、Values、Remove

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

uses
Generics.Collections;

procedure TForm1.Button1Click(Sender: TObject);
var
Dictionary: TDictionary<string, Integer>;
k: string;
v: Integer;
str: string;
begin
Dictionary := TDictionary<string, Integer>.Create;
//添加
Dictionary.Add('n1', 111);
Dictionary.Add('n2', 222);
Dictionary.Add('n3', 333);
//访问
ShowMessage(IntToStr(Dictionary['n2'])); //222
ShowMessage(IntToStr(Dictionary.Items['n2'])); //222
//遍历keys
str := '';
for k in Dictionary.Keys do str := str + k + ' ';
ShowMessage(str); //n2 n3 n1 顺序乱了？
//遍历Values
str := '';
for v in Dictionary.Values do str := str + IntToStr(v) + ' ';
ShowMessage(str); //222 333 111
//删除
Dictionary.Remove('n1');
str := '';
for k in Dictionary.Keys do str := str + IntToStr(Dictionary[k]) + ' ';
ShowMessage(str); //222 333
//count clear
ShowMessage(IntToStr(Dictionary.Count)); //2
Dictionary.Clear;
ShowMessage(IntToStr(Dictionary.Count)); //0
Dictionary.Free;
end;

end.