关于类的入门例子(3): Create 与 Destroy

//类单元
unit Person;

interface
uses
  Dialogs;

type
  TPerson = class(TObject)
  private
    FName: string;
    FAge: Integer;
  public
    constructor Create(strName: string; intAge: Integer);
    destructor Destroy; override;
    function GetName: string;
    function GetAge: Integer;
    procedure SetName(const strName: string);
    procedure SetAge(const intAge: Integer);
  end;

implementation

{ TPerson }

constructor TPerson.Create(strName: string; intAge: Integer);
begin
  inherited Create; //这里的 Create 不能省略, 因为参数不一样
  FName := strName;
  if intAge<0 then intAge := 0;
  FAge := intAge;
end;

destructor TPerson.Destroy;
begin
  ShowMessage(FName + '向你问好!');
  //inherited Destroy;
  inherited;  //省略就是继承同名方法
end;

function TPerson.GetName: string;
begin
  Result := FName;
end;

function TPerson.GetAge: Integer;
begin
  Result := FAge;
end;

procedure TPerson.SetName(const strName: string);
begin
  FName := strName;
end;

procedure TPerson.SetAge(const intAge: Integer);
begin
  if intAge<0 then FAge := 0 else FAge := intAge;
end;

end.


//测试:
uses Person;

procedure TForm1.Button1Click(Sender: TObject);
var
  PersonOne: TPerson;
begin
  PersonOne := TPerson.Create('wy',99);
  ShowMessage('姓名:' + PersonOne.GetName + '; 年龄:' +
    IntToStr(PersonOne.GetAge));  //姓名:wy; 年龄:99

  PersonOne.SetName('万一');
  PersonOne.SetAge(100);
  ShowMessage('姓名:' + PersonOne.GetName + '; 年龄:' +
    IntToStr(PersonOne.GetAge));  //姓名:万一; 年龄:100

  PersonOne.Free;  //万一向你问好!
end;