RegisterComponents (C++)

Description

This is the defs file for the RegisterComponents project.

class PACKAGE TDemoLabel : public TGraphicControl { private: TWinControl* FFocusControl;

Code

	void __fastcall SetFocusControl(TWinControl* Value);
	void __fastcall CMDialogChar(TWMKey& Message);
	void __fastcall CMTextChanged(TMessage& Message);

protected:
	virtual void __fastcall Notification(TComponent* AComponent, TOperation Operation);
	virtual void __fastcall Paint(void);

public:
	__fastcall virtual TDemoLabel(TComponent* AOwner);

__published:
	__property Caption ;
	__property Color ;
	__property TWinControl* FocusControl = {read=FFocusControl, write=SetFocusControl, nodefault};
	__property Font ;
	__property ParentColor ;
	__property ParentFont ;
public:
	__fastcall virtual ~TDemoLabel(void) { }

BEGIN_MESSAGE_MAP
  MESSAGE_HANDLER(CM_DIALOGCHAR, TWMKey, CMDialogChar);
  MESSAGE_HANDLER(CM_TEXTCHANGED, TMessage, CMTextChanged);
END_MESSAGE_MAP(TGraphicControl);
};

Uses

• System.Classes.RegisterComponents ( fr | de | ja )
• System.Classes.TComponent.FreeNotification ( fr | de | ja )=Description=

The following code registers several components, some on the MySystem palette page that already exist, and some on a new palette page that is created when the components are installed.

Code

void __fastcall PACKAGE Register()
{
  TComponentClass classes[1] = {__classid(TDemoLabel)};
  RegisterComponents("Samples", classes, 0);
  RegisterComponents("MySystem", classes, 0);
}

__fastcall TDemoLabel::TDemoLabel(TComponent *AOwner):
	TGraphicControl(AOwner)
{
  FComponentStyle >> csInheritable;
  Width=64;
  Height=13;
}

void __fastcall	TDemoLabel::Notification(TComponent *AComponent, TOperation Operation)
{
  TGraphicControl::Notification(AComponent, Operation);
  if ((Operation == opRemove)  && (AComponent == FFocusControl))
    FFocusControl = 0;
}

void __fastcall	TDemoLabel::SetFocusControl(TWinControl *Value)
{
  FFocusControl = Value;

  // Calling FreeNotification ensures that this component 
  // will receive an opRemove when Value is either removed 
  // from its owner or destroyed.

  Value->FreeNotification(Value);
}

void __fastcall	TDemoLabel::Paint()
{
  TRect	Rect = ClientRect;
  Canvas->Font = Font;
  Canvas->Brush->Color = Color;
  Canvas->FillRect(Rect);
  DrawText(
	Canvas->Handle,
	Caption.t_str(),
	Caption.Length(),
	&Rect,
	DT_EXPANDTABS | DT_WORDBREAK | DT_LEFT);
}

void __fastcall	TDemoLabel::CMDialogChar(TCMDialogKey &Message)
{
  if (FFocusControl != NULL &&
      Enabled == true &&
      IsAccel(Message.CharCode, Caption))
      if (FFocusControl->CanFocus()){
        FFocusControl->SetFocus();
        Message.Result = 1;
      }
}

void __fastcall	TDemoLabel::CMTextChanged(TMessage &Message)
{
  Invalidate();
}

Uses

• System.Classes.RegisterComponents ( fr | de | ja )
• System.Classes.TComponent.FreeNotification ( fr | de | ja )