Delphi实现静态变量

C++有静态变量，static关键字描述，其实Delphi也可以做到。

以前一般采用的是const方法来实现，现在的Delphi可以用class关键字来实现。

附代码如下，两种方式具有示例。

unit Unit6;
 
 interface
 
 uses
   Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
   Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;
 
 type
   TTestClass = class
   private
     {$J+}
     const FTest : integer = 0;
     {$J-}
     class var FTest2 : integer;
     function GetTest: integer;
     function GetTest2: integer;
   public
     constructor Create;virtual;
 
     property Test : integer read GetTest;
     property Test2 : integer read GetTest2;
   end;
 
   TForm6 = class(TForm)
     Button1: TButton;
     procedure Button1Click(Sender: TObject);
   private
     { Private declarations }
   public
     { Public declarations }
   end;
 
 var
   Form6: TForm6;
 
 implementation
 
 {$R *.dfm}
 
 { TTestClass }
 
 constructor TTestClass.Create;
 begin
   Inc(FTest);
   Inc(FTest2);
 end;
 
 function TTestClass.GetTest: integer;
 begin
   Result := FTest;
 end;
 
 function TTestClass.GetTest2: integer;
 begin
   Result := FTest2;
 end;
 
 procedure TForm6.Button1Click(Sender: TObject);
 var
   ATest : TTestClass;
 begin
   ATest := TTestClass.Create;
   Caption := IntToStr(ATest.GetTest)+':'+IntToStr(ATest.GetTest2);
 end;
 
 end.