template design question

[GNiewerth]

Hi,

I´m messing around with the borland VCL and have to accomplish the following task: There are many types (like TStaticText, TLabel, TEdit ...) that have properties with the same name, but unfortunately there´s no common base class with these properties made public, so I can´t use

((TWinControl *) pObject)->Text = "Hello World";

Example:

class TWinControl 
{
   protected:
     AnsiString  Caption;
...
};

class TLabel : public TWinControl
{
   public :
     AnsiString Caption;
...
};

class TStaticText : public TWinControl
{
   public:
     AnsiString Caption;
};

I read component properties (text color, font style, etc.) from a file and have to assign these properties to different control types. My current naive approach is providing a function for each control type and perform customization inside that function:

void CustomizeLabel( TLabel *pLabel, TComponentProperties *pProps )
{
    pLabel->Text = pProps->Text;
   pLabel->Color = pProps->Color;
   ...
}

void CustomizeMenu( TMenu *pMenu, TComponentProperties *pProps )
{
...
}

void CustomizeButton( TButton *pButton, TComponentProperties *pProps )
{
...
}

My second approach is to use templates and traits to handle different control types:

template<class TTarget> TNoOp
{
   TNoOp( TObject *pTarget, TComponentProperties *pProps )
   {
  }
}


template<class TTarget> TCaptionSetter
{
   TCaptionSetter( TObject *pTarget, TComponentProperties *pProps )
   {
      ((TTarget *) pTarget)->Caption = pProps->Text;
  }
}

template<class TTarget> TColorSetter
{
   TColorSetter( TObject *pTarget, TComponentProperties *pProps )
   {
      ((TTarget *) pTarget)->Color = pProps->Color;
  }


template<class TTarget, class TTextHandler, class TColorHandler> class TCustomizer
{
   TCustomizer( TObject *pTarget, TComponentProperties *pProps )
   {
      TTextHandler( pTarget, pProps );
      TColorHandler( pTarget, pProps );
   }
}

Now I can use the following constructs to assign text and/or color:

// set caption and color
TCustomizer<TLabel, TCaptionSetter<TLabel>, TColorSetter<TLabel> Cust( pObj, pProps );

// set caption only, ignore color
TCustomizer<TMenu, TCaptionSetter<TMenu>, TNoOp<TMenu> Cust( pObj, pProps );

Using the code above I have to specify the type name for each of the traits, making the code less readable. The type names are redundant, because they´re already known by the class TCustomizer, so I want to get rid of the template spec for the traits. I´m quite new to templates and generic programming, is it possible to create a construct without specialized trait classes? Like

template<class TTarget, class TCaptionSetter, class TColorSetter> TCustomizer
{
   TCustomizer( TObject *pObj, TComponentProperties *pProps )
   {
      TCaptionSetter ts( pObj, pProps );
      TColorSetter     cs( pObj, pProps );
   }
}

I want to use the template this way:

TCustomizer<TLabel, TCaptionSetter, TNoOp> Cust( pObj, pProps );

Third approach (just coming in mind, I don´t know if it will work):

template<class TTarget, class TTextHandler, class TColorHandler> class TCustomizer
{
  TTarget                          *m_pTarget;
   TComponentProperties *m_pProps;

   class TColorSetter( TCustomizer<TTarget> *pCustom )
   {
      pCustom->Target->Color = pCustom->m_Props->Color;
   }

   class TCaptionSetter( TCustomizer<TTarget> *pCusom )
   {
      pCustom->Target->Caption = pCustom->m_Props->Text;
   }

   TCustomizer( TObject *pTarget, TComponentProperties *pProps )
   {
       m_pTarget = (TTarget *) pTarget;
       m_pProps  = pProps;

      TTextHandler th( this );
      TColorHandler tc( this );
   }
}

Can I use

TCustomizer<TLabel, TCustomizer::TTextSetter,TCustomizer::TColorSetter> Cust( pObj, pProps );

?
Edit: Third approach can´t work, please ignore.

Thanks in advance,
Guido