CContainedWindowT Class

This class implements a window contained within another object.

template <
   class TBase = CWindow,
   class TWinTraits = CControlWinTraits 
>
class CContainedWindowT :
   public TBase

Parameters

• TBase
  The base class of your new class. The default base class is CWindow.

• TWinTraits
  A traits class that defines styles for your window. The default is CControlWinTraits.

Remarks

CContainedWindowT implements a window contained within another object. CContainedWindowT's window procedure uses a message map in the containing object to direct messages to the appropriate handlers. When constructing a CContainedWindowT object, you specify which message map should be used.

CContainedWindowT allows you to create a new window by superclassing an existing window class. The Create method first registers a window class that is based on an existing class but uses CContainedWindowT::WindowProc. Create then creates a window based on this new window class. Each instance of CContainedWindowT can superclass a different window class.

CContainedWindowT also supports window subclassing. The SubclassWindow method attaches an existing window to the CContainedWindowT object and changes the window procedure to CContainedWindowT::WindowProc. Each instance of CContainedWindowT can subclass a different window.

When you use the Add control based on option in the ATL Project Wizard, the wizard will automatically add a CContainedWindowT data member to the class implementing the control. The following example shows how the contained window is declared:

public:
   // Declare a contained window data member
   CContainedWindow m_ctlEdit;

   // Initialize the contained window:
   // 1. Pass "Edit" to specify that the contained 
   //    window should be based on the standard 
   //    Windows Edit box
   // 2. Pass 'this' pointer to specify that CAtlEdit 
   //    contains the message map to be used for the 
   //    contained window's message processing
   // 3. Pass the identifier of the message map. '1'
   //    identifies the alternate message map declared
   //    with ALT_MSG_MAP(1)
   CAtlEdit()
      : m_ctlEdit(_T("Edit"), this, 1)
   {
      m_bWindowOnly = TRUE;
   }

// Declare the default message map, identified by '0'
BEGIN_MSG_MAP(CAtlEdit)
   MESSAGE_HANDLER(WM_CREATE, OnCreate)
   MESSAGE_HANDLER(WM_SETFOCUS, OnSetFocus)
   CHAIN_MSG_MAP(CComControl<CAtlEdit>)
// Declare an alternate message map, identified by '1'
ALT_MSG_MAP(1)
   MESSAGE_HANDLER(WM_CHAR, OnChar)
END_MSG_MAP()

// Define OnCreate handler
// When the containing window receives a WM_CREATE
// message, create the contained window by calling
// CContainedWindow::Create
LRESULT OnCreate(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, 
   BOOL& /*bHandled*/)
{
   RECT rc;
   GetWindowRect(&rc);
   rc.right -= rc.left;
   rc.bottom -= rc.top;
   rc.top = rc.left = 0;
   m_ctlEdit.Create(m_hWnd, rc, _T("hello"), WS_CHILD | WS_VISIBLE | 
      ES_MULTILINE | ES_AUTOVSCROLL);
   return 0;
}

Requirements

Header: atlwin.h

See Also

Concepts

CContainedWindowT Members

CWindow Class

CWindowImpl Class

CMessageMap Class

BEGIN_MSG_MAP

ALT_MSG_MAP

ATL Class Overview