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。

 1 unit Unit6;
 2 
 3 interface
 4 
 5 uses
 6   Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
 7   Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;
 8 
 9 type
10   TTestClass = class
11   private
12     {$J+}
13     const FTest : integer = 0;
14     {$J-}
15     class var FTest2 : integer;
16     function GetTest: integer;
17     function GetTest2: integer;
18   public
19     constructor Create;virtual;
20 
21     property Test : integer read GetTest;
22     property Test2 : integer read GetTest2;
23   end;
24 
25   TForm6 = class(TForm)
26     Button1: TButton;
27     procedure Button1Click(Sender: TObject);
28   private
29     { Private declarations }
30   public
31     { Public declarations }
32   end;
33 
34 var
35   Form6: TForm6;
36 
37 implementation
38 
39 {$R *.dfm}
40 
41 { TTestClass }
42 
43 constructor TTestClass.Create;
44 begin
45   Inc(FTest);
46   Inc(FTest2);
47 end;
48 
49 function TTestClass.GetTest: integer;
50 begin
51   Result := FTest;
52 end;
53 
54 function TTestClass.GetTest2: integer;
55 begin
56   Result := FTest2;
57 end;
58 
59 procedure TForm6.Button1Click(Sender: TObject);
60 var
61   ATest : TTestClass;
62 begin
63   ATest := TTestClass.Create;
64   Caption := IntToStr(ATest.GetTest)+':'+IntToStr(ATest.GetTest2);
65 end;
66 
67 end.