请问我创建的监视文件拖动的控件的属性怎么显示不出来?

Question

unit DragFilesMonitor;interfaceuses
    Controls,Classes,Types,messages;procedure Register;type
    TDropFilesEvent = procedure(Receiver:TWinControl;const FileName:TStrings;
        const FilesCount:integer; const DropPoint:TPoint) of object;
    TDragFilesMonitor = class(TComponent)
    private
        FAcceptFilesControl:TWinControl; 
        OldWindowProc:TWndMethod;        
        FFilesName:TStrings;
        FOnDropFiles:TDropFilesEvent;
        procedure SetAcceptFilesControl(const Value:TWinControl);
    protected
        procedure NewWindowProc(var message:TMessage);
        procedure Notification(AComponent:TComponent;Operation:Toperation);override;
    public
        constructor create(AOwner:TComponent);override;
        destructor  destroy;override;
    published{***********属性和事件都没有在ObjectInspector中显示,为什么?***********}
        property AcceptFilesControl:TWinControl read FAcceptFilesControl 
                                   write  FAcceptFilesControl;
        property OnDropFiles:TDropFilesEvent read FOnDropFiles write FOnDropFiles;
    end;{TGragFilesMonitor}implementationuses
    ShellApi,SysUtils;
constructor TDragFilesMonitor.create(AOwner:TComponent);
begin
    inherited;
    FFilesName:=TStringList.create;
end;destructor TDragFilesMonitor.destroy;
begin
    if Assigned(FAcceptFilesControl) then
        DragAcceptFiles(FAcceptFilesControl.handle,false);
    FreeAndNil(FFilesName);
    inherited;
end;procedure TDragFilesMonitor.SetAcceptFilesControl(const Value:TWinControl);
begin
    if FAcceptFilesControl<>value then begin
        if Assigned(value)and(not(csDesigning in ComponentState)) then begin
            DragAcceptFiles(Value.handle,true);
            OldWindowProc:=Value.WindowProc;
            value.windowProc:=NewWindowProc;
        end;
        FacceptFilesControl:=value;
        FAcceptFilesControl.FreeNotification(self);
    end;
end;procedure TDragFilesMonitor.NewWindowProc(var message:Tmessage);
var
    count,index,hDrop:integer;
    PFileName:Pchar;
    p:TPoint;
begin
    if message.Msg=WM_DROPFILES then begin
        hDrop:=message.WParam;
        FFilesName.clear;
        getmem(PFileName,260);
        count:=dragqueryfile(hdrop,$FFFFFFFF, pfilename,255);
        for index:=0 to count-1 do  begin
            dragqueryfile(hdrop,index,pfilename,0);
            FFilesName.add(PFileName);
        end;{for}
        DragFinish(hDrop);
        if Assigned(FOnDropFIles) then
            FOnDropFiles(FAcceptFilesControl,FFilesName,count,p);
        FreeMem(PFileName);
        DragFinish(hdrop);
    end else
        OldWindowProc(message);
end;procedure TDragFilesMonitor.Notification(Acomponent:TComponent;
        Operation:TOperation);
begin
    inherited;
    if (AComponent=FAcceptFilesControl)and(Operation=opRemove) then
        FAcceptFilesControl:=nil;
end;procedure Register;
begin
    RegisterComponents('MyComponent',[TDragFilesMonitor]);
end;end.