Add controls inheritance to your application

If you need to add new functionality to standard Command Bar controls (CXTPControlButton, CXTPControlPopup, CXTPControlComboBox, CXTPControlEdit) you must create a new class inherited from one of these and override some virtual methods. This tutorial describes how to create custom Combo Box.

Imagine that you need a combo box with uppercase letters only (When users enter a character it automatically becomes uppercase)

1. Create a new class inherited from CXTPControlComboBox

   class CControlComboBoxEx: public CXTPControlComboBox
   {
       public:
   };
   

2. To create custom edit we must override CreateEditControl method and add a new Edit Control inherited from CXTPControlComboBoxEditCtrl

   class CControlComboBoxEx: public CXTPControlComboBox
   {
   public:
       CXTPControlComboBoxEditCtrl* CreateEditControl()
       {
           return new CControlComboBoxEditEx();
       }
   };
   
   class CControlComboBoxEditEx : public CXTPControlComboBoxEditCtrl
   {
   };
   

3. Add OnChar handler to automatically uppercase the characters that the user entered

   class CControlComboBoxEditEx : public CXTPControlComboBoxEditCtrl
   {
   public:
       afx_msg void OnChar(UINT nChar, UINT nRepCnt, UINT nFlags);
   
       DECLARE_MESSAGE_MAP()
   };
   
   BEGIN_MESSAGE_MAP(CControlComboBoxEditEx, CXTPControlComboBoxEditCtrl)
       ON_WM_CHAR()
   END_MESSAGE_MAP()
   
   void CControlComboBoxEditEx::OnChar(UINT nChar, UINT nRepCnt, UINT nFlags)
   {
       CString strChar((TCHAR)nChar), strUpper((TCHAR)nChar);
       strUpper.MakeUpper();
   
       if (strChar != strUpper) ReplaceSel(strUpper, TRUE);
       else CXTPControlComboBoxEditCtrl::OnChar(nChar,
                                               nRepCnt, nFlags);
   
   }
   

4. If your application uses customization you must add methods to restore your combo box after the program reloads.

   Add standard DECLARE and IMPLEMENT macros:

    class CControlComboBoxEx: public CXTPControlComboBox
    {
        DECLARE_XTP_CONTROL(CControlComboBoxEx)
    public:
        CXTPControlComboBoxEditCtrl* CreateEditControl()
        {
            return new CControlComboBoxEditEx();
        }
    };
    IMPLEMENT_XTP_CONTROL(CControlComboBoxEx, CXTPControlComboBox)
   

   If your control has its own variables that need to be stored/restored you must override Copy and Serialize methods:

   class CControlComboBoxEx: public CXTPControlComboBox
   {
       …
   
   protected:
       void Copy(CXTPControl* pControl, BOOL bRecursive = FALSE);
       virtual void Serialize(CArchive& ar);
   
   protected:
       CString m_strMask;
   };
   
   void CControlComboBoxEx::Copy(
           CXTPControl* pControl, BOOL bRecursive)
   {
       ASSERT_KINDOF(CControlComboBoxEx, pControl);
   
       m_strMask = ((CControlComboBoxEx*)pControl)->m_strMask;
   
       CXTPControlComboBox::Copy(pControl, bRecursive);
   }
   void CControlComboBoxEx::Serialize(CArchive& ar)
   {
       CXTPControlComboBox::Serialize(ar);
   
       if (ar.IsStoring())
       {
           ar << m_strMask;
       }
       else
       {
           ar >> m_strMask;
       }
   }
   

5. Now you can create your control in the OnCreateControl handler

   BEGIN_MESSAGE_MAP(CMainFrame, CMDIFrameWnd)
       ON_XTP_CREATECONTROL()
   END_MESSAGE_MAP()
   
   int CMainFrame::OnCreateControl(
                   LPCREATECONTROLSTRUCT lpCreateControl)
   {
       if (lpCreateControl->nID == ID_POPUP_COMBO)
       {
           CXTPControlComboBox* pComboFind =
           (CXTPControlComboBox*)CControlComboBoxEx::CreateObject();
           pComboFind->SetDropDownListStyle();
           pComboFind->SetFlags(xtpFlagManualUpdate);
   
           lpCreateControl->pControl = pComboFind;
           return TRUE;
       }
       return FALSE;
   }