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);
  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 }

  {通过 Keys 遍历 Values}
  str := '';
  for K in Dictionary.Keys do str := str + IntToStr(Dictionary[K]) + ' ';
  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.