MFC Multi-line CComboBox

BoxDlg.cpp

// BoxDlg.cpp : implementation file
//
 
#include "stdafx.h"
#include "Box.h"
#include "BoxDlg.h"
 
#ifdef _DEBUG
#define new DEBUG_NEW
#endif
 
// CBoxDlg dialog
CBoxDlg::CBoxDlg(CWnd* pParent /*=NULL*/)
	: CDialog(CBoxDlg::IDD, pParent)
{
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}
 
void CBoxDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	DDX_Control(pDX, IDC_COMBO1, m_combo);
}
 
BEGIN_MESSAGE_MAP(CBoxDlg, CDialog)
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()
 
// CBoxDlg message handlers
 
BOOL CBoxDlg::OnInitDialog()
{
	CDialog::OnInitDialog();
 
	// Set the icon for this dialog.  The framework does this automatically
	//  when the application's main window is not a dialog
	SetIcon(m_hIcon, TRUE);			// Set big icon
	SetIcon(m_hIcon, FALSE);		// Set small icon
 
	// TODO: Add extra initialization here
	m_combo.Init();
	m_combo.AddItem("Introducing uppercuts crisps!");
	m_combo.AddItem("Today is a good day to go to Orchard Road for shopping");
	m_combo.AddItem("Finely sliced potato chips, delicately seasoned with the most authentic.");
	m_combo.AddItem("192.0.2.123/16 is online. Please disconnect the device");
	m_combo.SetCurSel(0);
	return TRUE;  // return TRUE  unless you set the focus to a control
}
 
// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.
 
void CBoxDlg::OnPaint()
{
	if (IsIconic())
	{
		CPaintDC dc(this); // device context for painting
 
		SendMessage(WM_ICONERASEBKGND, reinterpret_cast(dc.GetSafeHdc()), 0);
 
		// Center icon in client rectangle
		int cxIcon = GetSystemMetrics(SM_CXICON);
		int cyIcon = GetSystemMetrics(SM_CYICON);
		CRect rect;
		GetClientRect(&rect);
		int x = (rect.Width() - cxIcon + 1) / 2;
		int y = (rect.Height() - cyIcon + 1) / 2;
 
		// Draw the icon
		dc.DrawIcon(x, y, m_hIcon);
	}
	else
	{
		CDialog::OnPaint();
	}
}
 
// The system calls this function to obtain the
// cursor to display while the user drags
// the minimized window.
HCURSOR CBoxDlg::OnQueryDragIcon()
{
	return static_cast(m_hIcon);
}

BoxDlg.h

#pragma once
#include "mybox.h"
#include "afxwin.h"
 
// CBoxDlg dialog
class CBoxDlg : public CDialog
{
// Construction
public:
CBoxDlg(CWnd* pParent = NULL);	// standard constructor
 
// Dialog Data
enum { IDD = IDD_BOX_DIALOG };
 
protected:
virtual void DoDataExchange(CDataExchange* pDX); 
 
// Implementation
protected:
HICON m_hIcon;
CMyBox m_combo;
 
// Generated message map functions
virtual BOOL OnInitDialog();
afx_msg void OnPaint();
afx_msg HCURSOR OnQueryDragIcon();
DECLARE_MESSAGE_MAP()
};

MyBox.cpp

// ODrawCombo.cpp : implementation file
//
 
#include "stdafx.h"
#include "mybox.h"
 
// CMyBox
 
IMPLEMENT_DYNAMIC(CMyBox, CComboBox)
CMyBox::CMyBox()
{
}
 
CMyBox::~CMyBox()
{
}
 
BEGIN_MESSAGE_MAP(CMyBox, CComboBox)
END_MESSAGE_MAP()
 
// CMyBox message handlers
 
void CMyBox::Init()
{
}
 
void CMyBox::AddItem(CString nItem)
{
	this->AddString(nItem);
}
 
void CMyBox::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{
	 ASSERT(lpDrawItemStruct->CtlType == ODT_COMBOBOX);
	 if(lpDrawItemStruct->itemID != 0xffffffff)
	 {
        // 1 - Get combobox item ID
		UINT id = (UINT) (WORD) lpDrawItemStruct->itemID;
 
		// Consistency checks
		ASSERT(id == lpDrawItemStruct->itemID);
 
		// 2 - Get device context & item rectangle
		CDC dc;
		dc.Attach(lpDrawItemStruct->hDC);
 
		CRect rcItem = lpDrawItemStruct->rcItem;
		int nCurrentX = rcItem.left;
 
		// 3 - Select background and foreground
		// colors depending on item selected state
		COLORREF crBack, crFore;
		if(lpDrawItemStruct->itemState & ODS_SELECTED)
		{
			crBack = ::GetSysColor(COLOR_HIGHLIGHT);
			crFore = ::GetSysColor(COLOR_HIGHLIGHTTEXT);
		}
		else
		{
			crBack = ::GetSysColor(COLOR_WINDOW);
			crFore = ::GetSysColor(COLOR_WINDOWTEXT);
		}
 
		// 4 - Fill item background
		CRect rcBack(nCurrentX, rcItem.top, rcItem.right, rcItem.bottom);
		CBrush brFill(crBack);
		dc.FillRect(&rcBack, &brFill);
 
		// 5 - Draw item color rectangle
		CBrush brColor(::GetSysColor(COLOR_WINDOWTEXT));
		CBrush* pOldBrush = dc.SelectObject(&brColor);
		CRect rcColor(nCurrentX, rcItem.top, nCurrentX, rcItem.bottom);
		dc.Rectangle(rcColor);
		dc.SelectObject(pOldBrush);
 
        // 6 - Draw item text
		COLORREF crOldTextColor = dc.SetTextColor(crFore);
		int nOldBkMode = dc.SetBkMode(TRANSPARENT);
		CString str;
		this->GetLBText(id, str);
		dc.DrawText(str, -1, rcItem, DT_LEFT|DT_WORDBREAK);
		dc.SetTextColor(crOldTextColor);
		dc.SetBkMode(nOldBkMode);
		dc.Detach();
	}
}
 
void CMyBox::MeasureItem(LPMEASUREITEMSTRUCT lpMeasureItemStruct)
{
	/*DWORD dwStyle = ::GetWindowLong( m_hWnd, GWL_STYLE );*/
	/*ASSERT( dwStyle & CBS_DROPDOWNLIST );*/
 
	CFont* pFont = GetFont();
	CFont* pOldFont = 0;
	CString str;
	CDC* pDC = GetDC();
	pOldFont = pDC->SelectObject(pFont);
 
	// Get text from combo box
	this->GetLBText(lpMeasureItemStruct->itemID, str);
 
	// Obtain rectangle that text is originally in
	CRect rc;
	GetClientRect(&rc);
	//GetWindowRect(&rc);
	rc.left = 0;
	rc.top = 0;
	rc.bottom = 0;
 
	// With the inclusion of DT_CALCRECT
	// this DrawText does not draw the text
	// it just measures the rectangle
	pDC->DrawText(str, str.GetLength(), &rc, DT_CALCRECT|DT_LEFT|DT_WORDBREAK);
	lpMeasureItemStruct->itemHeight = rc.bottom;
	pDC->SelectObject(pOldFont);
	ReleaseDC(pDC);
}

MyBox.h

#pragma once
 
// CMyBox
class CMyBox : public CComboBox
{
	DECLARE_DYNAMIC(CMyBox)
 
public:
	CMyBox();
	virtual ~CMyBox();
	void Init();
	void AddItem(CString nItem);
	virtual void DrawItem(LPDRAWITEMSTRUCT);
	virtual void MeasureItem(LPMEASUREITEMSTRUCT);
 
protected:
	DECLARE_MESSAGE_MAP()
};