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.