在前面的文章《Barcode Xpress使用教程：如何在Visual C++中作為COM對象使用（1）》中已經對在Visual C++中如何將Barcode Xpress作為一個導入的COM 對象使用的步驟做了一些講解，下面將繼續(xù)上文。

    三、初始化COM

    在COM函數(shù)可以被調用之前，這個必須先初始化COM庫，并且在程序退出之前必須關閉。在ReadBarcodeFromDIB.cpp文件中像下面這樣說明：

// CReadBarcodeFromDIBApp initialization
BOOL CReadBarcodeFromDIBApp::InitInstance()
{
// Initialize the COM library on the current apartment and identify
// the currency model as single-thread apartment (STA). Applications
// must initialize the COM
// library before they can call COM library functions other than
// CoGetMalloc and memory allocation functions.
HRESULT hRes = CoInitialize(NULL);
AfxEnableControlContainer();
 
// Standard initialization
// If you are not using these features and wish to reduce the size
// of your final executable, you should remove from the following
// the specific initialization routines you do not need.
 
#ifdef _AFXDLL
Enable3dControls(); // Call this when using MFC in a shared DLL
#else
Enable3dControlsStatic(); // Call this when linking to MFC statically
#endif
 
CReadBarcodeFromDIBDlg dlg;
m_pMainWnd = &dlg;
int nResponse = dlg.DoModal();
if (nResponse == IDOK)
{
// TODO: Place code here to handle when the dialog is
// dismissed with OK
}
else if (nResponse == IDCANCEL)
{
// TODO: Place code here to handle when the dialog is
// dismissed with Cancel
}
 
// Closes the COM library on the current apartment,
// unloads all DLLs loaded by apartment,
// frees any other resources that the apartment maintains, and
// forces all RPC connections on the apartment to close.
CoUninitialize();
 
// Since the dialog has been closed, return FALSE so that we exit the
// application, rather than start the application's message pump.
return FALSE;
}

四、創(chuàng)建BarcodeXpress COM對象

    要使用BarcodeXpress，需要創(chuàng)建一個BarcodeXpress COM實例。在對象被創(chuàng)建之后，對象的屬性和方法可以用于創(chuàng)建你的掃描應用程序。在ReadBarcodeFromDIB項目中，這個COM對象在 ReadBarcodeFromDIBDlg.cpp文件中如下創(chuàng)建：

// CReadBarcodeFromDIBDlg message handlers
BOOL CReadBarcodeFromDIBDlg::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
CWnd* pControl = NULL;
pControl = GetDlgItem(Description);
if (pControl)
{
pControl->SetWindowText(lpctstrDescription);
}
 
CRect oIXArea;
oIXArea.left = 25;
oIXArea.top = 215;
oIXArea.right = 725;
oIXArea.bottom = 636;
 
// Create an ImagXpress Object
m_ppCImagXpress = new CImagXpress(this, 1, (long) m_hWnd,
oIXArea.left, oIXArea.top, oIXArea.Width(), oIXArea.Height());
m_pImagXpress = m_ppCImagXpress->pImagXpress;
m_pImagXpress->PutCtlVisible(true);
m_pImagXpress->AutoSize = ISIZE_BestFit;
m_pImagXpress->ScrollBars = SB_Both;
m_pImagXpress->MenuSetEnabled(Menu_Context,TOOL_None, true);
 
// **Initialize Barcode. You must call BC_Open before
// **creating the first BarcodeXpress COM object. You cannot distribute applications using
// **BarcodeXpress COM objects without valid unlock codes.
// Create a BarcodeXpress class object. The BarcodeXpress
// class object automatically creates a Barcode Xpress
// COM object.
m_ppIBarcodeXpress = new CBarcodeXpress(this, 1);
 
// The SetSolutionName, SetSolutionKey and possibly the SetOEMLicenseKey method must be
// called to distribute the runtime.  Note that the SolutionName, SolutionKey and
// OEMLicenseKey values shown below are only examples.
//
//m_pBarcodeXpress->SetSolutionName("YourSolutionName");
//m_pBarcodeXpress->SetSolutionKey(12345, 12345, 12345, 12345);
//m_pBarcodeXpress->SetOEMLicenseKey("1.0.AStringForOEMLicensingContactAccusoftSalesForMoreInformation...");
//
//m_pImagXpress->SetSolutionName("YourSolutionName");
//m_pImagXpress->SetSolutionKey(12345, 12345, 12345, 12345);
//m_pImagXpress->SetOEMLicenseKey("1.0.AStringForOEMLicensingContactAccusoftSalesForMoreInformation...");
 
// Get the pointer to the created BarcodeXpress Barcode COM object.
// This is the pointer that you will use to access BarcodeXpress
// Barcode properties and methods.
m_pBarcodeXpress = m_ppIBarcodeXpress->pBarcodeXpress;
 
// Close the BarcodeXpress Barcode initialization.
// You must call this AFTER creating the first BarcodeXpress Barcode
// COM object
 
m_1D.SetCheck(BST_CHECKED);
m_selection = 0;
m_pImagXpress->FileName = "..\\..\\..\\..\\..\\..\\Common\\Images\\Barcode All Supported Types.tif";
return TRUE; // return TRUE unless you set the focus to a control
}