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.