覆蓋虛方法

unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs;type  TForm1 = class(TForm)    procedure FormCreate(Sender: TObject);  private    { Private declarations }  public    { Public declarations }  end;//夫類  TParent = class  protected    function MyFun(i: Integer): Integer; dynamic;  //動態方法    procedure MyProc; virtual;  //虛方法  end;//子類  TChild = class(TParent)  protected    function MyFun(i: Integer): Integer; override;  //覆蓋    procedure MyProc; override;  //覆蓋  end;var  Form1: TForm1;implementation{$R *.dfm}{ TParent }function TParent.MyFun(i: Integer): Integer;begin  Inc(i);  Result := i;end;procedure TParent.MyProc;begin  ShowMessage('Parent');end;{ TChild }function TChild.MyFun(i: Integer): Integer;begin  i := inherited MyFun(i);  //先調用夫類方法，被 +1；當然可以不調用  Inc(i);                   //子類再 +1  Result := i;end;procedure TChild.MyProc;begin  inherited;  //先調用夫類方法；當然可以不調用  ShowMessage('Child');end;//測試procedure TForm1.FormCreate(Sender: TObject);var  p: TParent;  c: TChild;begin  p := TParent.Create;  c := TChild.Create;  p.MyProc;  //Parent  c.MyProc;  //Parent; TChild  ShowMessage(IntToStr(p.MyFun(2)));  //3  ShowMessage(IntToStr(c.MyFun(2)));  //4  p.Free;  c.Free;end;end.