Delphi 系统[24]关键字和保留字 virtual、dynamic、abstract、inline、static - 类方法类型

{ 虚拟方法 }
TObject = class
public
  procedure Dispatch(var Message); virtual;
  destructor Destroy; virtual;
end;

---------------------------------------------------------------------------------------
{ 动态方法 }
TCustomForm = class
protected
  procedure DoHide; dynamic;
  procedure DoShow; dynamic;
end;

---------------------------------------------------------------------------------------
{ TStrings 中的抽象方法 }
TStrings = class
protected
  function Get(Index: Integer): string; virtual; abstract;{ 这里只需要定义，具体功能靠子类去实现 }
  function GetCount: Integer; virtual; abstract; { 这里只需要定义，具体功能靠子类去实现 }
end;

--------------------------------------------------------------------------------------
{ 内联函数 inline}
function Test(S: string): string; inline;
begin
  Result := ‘显示结果：‘ + S;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Caption := Test(Caption);
  { 此处调用了内联函数，所以，在编译时，此处的代码就被改成了 Caption := ‘显示结果：‘ + Caption; 直接将内联函数的代码搬过来进行编译 }
end;

type
  TFigure = class
    procedure Draw; virtual;
  end;
  TRectangle = class(TFigure)
    procedure Draw; override;
  end;
  TEllipse = class(TFigure)
    procedure Draw; override;
  end;

var
  Figure: TFigure;
begin
  Figure := TRectangle.Create;
  Figure.Draw;  // calls TRectangle.Draw
  Figure.Destroy;
  Figure := TEllipse.Create;
  Figure.Draw;  // calls TEllipse.Draw
  Figure.Destroy;
end;