Tree ComboBox Control

// TreeComboBox.cpp : implementation file
//

#include "stdafx.h"
#include "TreeComboBox.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CTreeComboBox

CTreeComboBox::CTreeComboBox()
	:m_bControlActive(FALSE)
	,m_bAlertBkg(FALSE)
	,m_bAlertText(FALSE)
	,m_nDroppedHeight(150)
	,m_nDroppedWidth(100)
{
	m_crAlertBkg = GetSysColor(COLOR_WINDOW);
	m_crAlertText = GetSysColor(COLOR_WINDOWTEXT);
	m_BrushAlert.CreateSolidBrush(m_crAlertBkg);
}

CTreeComboBox::~CTreeComboBox()
{
	m_BrushAlert.DeleteObject();
}


BEGIN_MESSAGE_MAP(CTreeComboBox, CComboBox)
	//{{AFX_MSG_MAP(CTreeComboBox)
	ON_WM_LBUTTONDOWN()
	ON_WM_LBUTTONDBLCLK()
	//}}AFX_MSG_MAP
	ON_MESSAGE(WMU_CLOSE_CONTROL, OnCloseControl)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CTreeComboBox message handlers

void CTreeComboBox::PreSubclassWindow() 
{
	// TODO: Add your specialized code here and/or call the base class

	CComboBox::PreSubclassWindow();

	CRect rect(0, 0, 0, 0);
	DWORD dwStyle =  WS_POPUP | WS_BORDER;
	CWnd* pWnd = &m_Tree;
	pWnd->CreateEx(0, WC_TREEVIEW, NULL, dwStyle, rect, GetParent(), 0, NULL);
	m_Tree.Init(this);

	GetClientRect(rect);
	SetDroppedWidth(rect.Width());
	SetDroppedHeight(m_nDroppedHeight);

	dwStyle = CBS_DROPDOWNLIST & GetStyle();
	ASSERT(CBS_DROPDOWNLIST == dwStyle);
}

BOOL CTreeComboBox::PreTranslateMessage(MSG* pMsg) 
{
	// TODO: Add your specialized code here and/or call the base class

	if(WM_KEYDOWN == pMsg->message && (VK_DOWN == pMsg->wParam || VK_F4 == pMsg->wParam))
	{
		DisplayTree();
		return TRUE;
	}

	return CComboBox::PreTranslateMessage(pMsg);
}

void CTreeComboBox::OnLButtonDown(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default

	m_bControlActive = ! m_bControlActive;
	if(m_bControlActive)
		DisplayTree();

//	CComboBox::OnLButtonDown(nFlags, point);
}

void CTreeComboBox::OnLButtonDblClk(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default

	OnLButtonDown(nFlags, point);

//	CComboBox::OnLButtonDblClk(nFlags, point);
}

void CTreeComboBox::TreeCtrlDone()
{
	CWnd* pParent = GetParent();

	if(pParent != NULL)
	{
		WPARAM wParam = MAKEWPARAM(GetDlgCtrlID(), CBN_CLOSEUP);
		pParent->SendMessage(WM_COMMAND, wParam, (LPARAM)m_hWnd);
	}
}

LRESULT CTreeComboBox::OnCloseControl(WPARAM wParam, LPARAM lParam)
{
	TreeCtrlDone();
	if(NULL != m_Tree.GetSafeHwnd())
	{
		m_Tree.ShowWindow(SW_HIDE);
		CToolTipCtrl* pTooltip = m_Tree.GetToolTips();
		if(NULL != pTooltip)
			pTooltip->Pop();
	}
	m_bControlActive = FALSE;
	if(GetCount())
		SetCurSel(0);
	SetFocus();

	return 1;
}

BOOL CTreeComboBox::OnChildNotify(UINT message, WPARAM wParam, LPARAM lParam, LRESULT* pLResult) 
{
	// TODO: Add your specialized code here and/or call the base class

	if((! m_bAlertText && ! m_bAlertBkg) || WM_CTLCOLOREDIT != message)
		return CComboBox::OnChildNotify(message, wParam, lParam, pLResult);

	HDC hdcChild = (HDC)wParam;
	if(NULL != hdcChild)
	{
		if(m_bAlertText)
			SetTextColor(hdcChild, m_crAlertText);
		if(m_bAlertBkg)
			SetBkColor(hdcChild, m_crAlertBkg);
		*pLResult = (LRESULT)(m_BrushAlert.GetSafeHandle());
	}

	return TRUE;
//	return CComboBox::OnChildNotify(message, wParam, lParam, pLResult);
}

void CTreeComboBox::DisplayTree()
{
	CRect rect;
	GetWindowRect(rect);

	int nScreenHeight = GetSystemMetrics(SM_CYSCREEN);
	int nDesiredDroppedHeight, nDroppedHeight = m_nDroppedHeight;

	if(NULL != m_Tree.GetSafeHwnd())
	{
		int nCount = 0;
		HTREEITEM hItem = m_Tree.GetRootItem();
		while(NULL != hItem)
		{
			hItem = m_Tree.GetNextSiblingItem(hItem);
			nCount++;
		}
		if(nCount > 1)
		{
			nDesiredDroppedHeight = nCount * (m_Tree.GetItemHeight() + GetSystemMetrics(SM_CXEDGE) / 2);
			if(nDesiredDroppedHeight > nScreenHeight / 2)
				nDesiredDroppedHeight = nScreenHeight / 2;
			if(nDroppedHeight < nDesiredDroppedHeight)
				nDroppedHeight = nDesiredDroppedHeight;
		}
	}

	if(rect.bottom + nDroppedHeight + GetSystemMetrics(SM_CYCAPTION) > nScreenHeight)
	{
		rect.top = rect.top - GetSystemMetrics(SM_CXEDGE) - nDroppedHeight;
		rect.bottom = nDroppedHeight + 1;
	}
	else
	{
		rect.top = rect.bottom;
		rect.bottom = nDroppedHeight;
	}
	rect.right = m_nDroppedWidth;

	m_Tree.Display(rect);
	SetCurSel(-1);
}

void CTreeComboBox::SetTitle(CString sTitle)
{
	if(GetCount())
	{
		SetCurSel(0);
		return;
	}

	ResetContent();
	AddString(sTitle);
	SetCurSel(0);
}

void CTreeComboBox::SetAlertColorBkg(const COLORREF crColor)
{
	m_crAlertBkg = crColor;
	m_BrushAlert.DeleteObject();
	m_BrushAlert.CreateSolidBrush(m_crAlertBkg);
}