全局变量和局部变量示例

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Button1: TButton;
    Button2: TButton;
    procedure FormShow(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

var
  GV: integer;                                    //定义全局变量

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);   //局部值按钮单击事件
var
  lv: integer;
begin
  lv := 10;
  lv := lv + 1;                                   //局部变量值加1
  edit2.Text := inttostr(lv);
end;

procedure TForm1.Button2Click(Sender: TObject);   //全局值按钮单击事件
begin
  gv := gv + 1;                                   //全局变量值加1
  edit1.Text := inttostr(gv);
end;

procedure TForm1.FormShow(Sender: TObject);       //窗体显示事件
begin
  GV := 10;                                       //全局变量赋初值
  edit1.Text := inttostr(gv);
  edit2.Text := inttostr(gv);
end;

end.