Accessing Excel Spreadsheets via C++

/*
Copyright (c) 2006 KnowNow, Inc.  All rights reserved.

@KNOWNOW_LICENSE_START@

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*/

/////////////////////////////////////////////////////////////////////////////
//
// MainDlg.cpp : implementation of the CMainDlg class
//
/////////////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "resource.h"

#include "MainDlg.h"

#include "AboutDlg.h"
#include "FileFilter.h"

/////////////////////////////////////////////////////////////////////////////

BOOL CMainDlg::PreTranslateMessage( MSG* pmsg )
{
	return ( IsDialogMessage( pmsg ) );
}

BOOL CMainDlg::OnIdle( )
{
	return ( FALSE );
}

/////////////////////////////////////////////////////////////////////////////

BOOL CMainDlg::OnInitDialog( HWND hwndFocus, LPARAM lParam )
{
	DoDataExchange( FALSE );

	CenterWindow();

	SetIcon( (HICON) ::LoadImage(_Module.GetResourceInstance(), MAKEINTRESOURCE(IDR_MAINFRAME), IMAGE_ICON, ::GetSystemMetrics( SM_CXICON ), ::GetSystemMetrics( SM_CYICON ), LR_DEFAULTCOLOR ), TRUE );
	SetIcon( (HICON) ::LoadImage(_Module.GetResourceInstance(), MAKEINTRESOURCE(IDR_MAINFRAME), IMAGE_ICON, ::GetSystemMetrics( SM_CXSMICON ), ::GetSystemMetrics( SM_CYSMICON ), LR_DEFAULTCOLOR ), FALSE );

	CMessageLoop* pLoop = _Module.GetMessageLoop();
	ATLASSERT(pLoop != NULL);

	pLoop->AddMessageFilter( this );
	pLoop->AddIdleHandler( this );

	UIAddChildWindowContainer( m_hWnd );

	return ( TRUE );
}

/////////////////////////////////////////////////////////////////////////////

void CMainDlg::OnLoad( WORD wNotifyCode, WORD wID, HWND hwndCtrl )
{
	// Nuke the contents of the list control.
	m_list.DeleteAllItems( );

	while ( m_list.DeleteColumn( 0 ) );

	// Get the Excel file from the user.
	AFileFilter	ff( _T("Excel Files|*.xls|All Files|*.*||") );

	CFileDialog	dlgFile( TRUE, 
						 _T("xls"), 
						 _T(""), 
						 OFN_FILEMUSTEXIST | OFN_HIDEREADONLY, 
						 ff, 
						 m_hWnd
					   );

	dlgFile.m_ofn.lpstrTitle = _T("Select the Excel File to Load");

	if ( dlgFile.DoModal( ) != IDOK )
		return;

	// Load the Excel application in the background.
	Excel::_ApplicationPtr pApplication;

	if ( FAILED( pApplication.CreateInstance( _T("Excel.Application") ) ) )
	{
		Errorf( _T("Failed to initialize Excel::_Application!") );
		return;
	}

	_variant_t	varOption( (long) DISP_E_PARAMNOTFOUND, VT_ERROR );

	Excel::_WorkbookPtr pBook = pApplication->Workbooks->Open( dlgFile.m_szFileName, varOption, varOption, varOption, varOption, varOption, varOption, varOption, varOption, varOption, varOption, varOption, varOption );

	if ( pBook == NULL )
	{
		Errorf( _T("Failed to open Excel file!") );
		return;
	}

	Excel::_WorksheetPtr pSheet = pBook->Sheets->Item[ 1 ];

	if ( pSheet == NULL )
	{
		Errorf( _T("Failed to get first Worksheet!") );
		return;
	}

	// Load the column headers.
	Excel::RangePtr pRange = pSheet->GetRange( _bstr_t( _T("A1") ), _bstr_t( _T("Z1" ) ) );

	if ( pRange == NULL )
	{
		Errorf( _T("Failed to get header cell range( A1:Z1 )!") );
		return;
	}

	int			iColumns = 0;

	for ( int iColumn = 1; iColumn < 26; ++iColumn )
	{
		_variant_t	vItem = pRange->Item[ 1 ][ iColumn ];
		_bstr_t		bstrText( vItem );

		if ( bstrText.length( ) == 0 )
			break;

		m_list.AddColumn( bstrText, iColumns++ );
	}

	// Load the rows (up to the first blank one).
	pRange = pSheet->GetRange( _bstr_t( _T("A2") ), _bstr_t( _T("Z16384" ) ) );

	for ( int iRow = 1; ; ++iRow )
	{
		for ( int iColumn = 1; iColumn <= iColumns; ++iColumn )
		{
			_variant_t	vItem = pRange->Item[ iRow ][ iColumn ];
			_bstr_t		bstrText( vItem );

			if ( bstrText.length( ) == 0 )
				break;

			if ( iColumn == 1 )
				m_list.AddItem( iRow - 1, 0, bstrText );
			else
				m_list.SetItemText( iRow - 1, iColumn - 1, bstrText );
		}

		if ( iColumn == 1 )
			break;
	}

	// Make it all look pretty.
	for ( int iColumn = 1; iColumn <= iColumns; ++iColumn )
		m_list.SetColumnWidth( iColumn, LVSCW_AUTOSIZE_USEHEADER );

	// Don't save any inadvertant changes to the .xls file.
	pBook->Close( VARIANT_FALSE );

	// Need to quit, otherwise Excel remains active and locks the .xls file.
	pApplication->Quit( );

	return;
}

/////////////////////////////////////////////////////////////////////////////

void CMainDlg::OnCloseCommand( WORD wNotifyCode, WORD wID, HWND hwndCtrl )
{
	DestroyWindow( );

	::PostQuitMessage( wID );

	return;
}

void CMainDlg::OnAppAbout( WORD wNotifyCode, WORD wID, HWND hwndCtrl )
{
	CAboutDlg	dlg;

	dlg.DoModal( );

	return;
}

/////////////////////////////////////////////////////////////////////////////

void CMainDlg::Errorf( LPCTSTR pszFormat, ... )
{
	CString		str;

	va_list	argList;

	va_start( argList, pszFormat );

	str.FormatV( pszFormat, argList );

	::AtlMessageBox( m_hWnd, (LPCTSTR) str, _T("WTLExcel Error"), MB_ICONHAND | MB_OK );

	return;
}