MFC 打印功能，无打印预览

对话框打印，网上一搜一大堆，基本分2类：

A类： CPrintDialog.DoModal，然后在模态对话框里选打印机、打印配置；

B类：GetPrinterDeviceDefaults，调用默认打印机。

我的工作内容是理解以上2类后，再根据MSDN，实现MDF对话框后台指定打印机打印。

废话不多说，上菜~

功能：基于对话框的MFC打印（非文档视图结构），指定打印机，后台打印（不弹出对话框）

思路：

1、枚举打印机，并选择其中一个；

2、CPrintDialog实例指定到选中的打印机；

3、CPrintDialog后台打印

具体实现：

1、变量（控件）。在对话框上添加一个combobox（IDC_COMBO1，对应变量m_cboPrint）、一个edit（IDC_EDIT1），edit允许回车，多行（代码就不贴了，知道MFC应该就懂）；

2、在OnInitDialog里枚举打印机设备，如果报函数未定义，加入头文件#include <winspool.h>

需要调用两次EnumPrinters函数，第一次的到结构体的大小，第二次得到打印机列表

// TODO: 在此添加额外的初始化代码
        	DWORD dwNeeded;
        	DWORD dwReturn;
        	DWORD dwFlag = PRINTER_ENUM_CONNECTIONS | PRINTER_ENUM_LOCAL;

EnumPrinters(dwFlag, NULL, 4, NULL, 0, &dwNeeded, &dwReturn);

PRINTER_INFO_4* p4;
p4 = new PRINTER_INFO_4[dwNeeded];
EnumPrinters(dwFlag, NULL, 4, (PBYTE)p4, dwNeeded, &dwNeeded, &dwReturn);

for (int i = 0; i<(int)dwReturn; i++)
	this->m_cboPrint.AddString(p4[i].pPrinterName);

delete []p4;

3、操作对话框，在IDC_EDIT1里输入打印的内容，在IDC_COMBO1里选中打印机；

4、打印（我是用OK按钮打印的，大家随便）

// TODO: 在此添加控件通知处理程序代码
//	CDialogEx::OnOK();
	this->UpdateData();
 
CString strMessage;
CString strPrintDevice;

this->GetDlgItem(IDC_EDIT1)->GetWindowTextW(strMessage);
strMessage += _T("\r\n");		//添加结尾，方便后面循环读取打印数据

this->GetDlgItem(IDC_COMBO1)->GetWindowTextW(strPrintDevice);

DWORD dwFlag = PD_ALLPAGES | PD_NOPAGENUMS | PD_USEDEVMODECOPIES | PD_HIDEPRINTTOFILE;	//打印配置界面的按钮可用性，因为后台打印，其实这个配置没什么意义

CPrintDialog pPrintdlg(FALSE, dwFlag, this);											//CPrintDialog实例化，因为MFC的打印设备无关性，可以理解为这就是一台打印机

HGLOBAL hDevMode = NULL;
HGLOBAL hDevNames = NULL;
if (GetPrinterDevice(strPrintDevice.GetBuffer(0), &hDevNames, &hDevMode))				//获得指定打印机的配置、名字
	AfxGetApp()->SelectPrinter(hDevNames, hDevMode);
else
	AfxMessageBox(_T("Failed to select custom printer"));

strPrintDevice.ReleaseBuffer();

pPrintdlg.m_pd.hDevMode = hDevMode;														//让pPrintdlg使用我们指定的打印机
pPrintdlg.m_pd.hDevNames = hDevNames;

CDC dc;
dc.Attach(pPrintdlg.CreatePrinterDC());													//后台打印创建法，如果需要弹出打印对话框，请用DoModal
/*弹出打印对话框*/
//dc.Attach((HDC)pPrintdlg.DoModal());										

DOCINFO di;																				//下面的内容网上很多，就不解释了
di.cbSize = sizeof(DOCINFO);
di.lpszDocName = _T("有驱打印测试");
di.lpszDatatype = NULL;
di.lpszOutput = NULL;
di.fwType = 0;

dc.StartDocW(&di);
dc.StartPage();
dc.SetMapMode(MM_TEXT);

CRect recPrint(0, 0, dc.GetDeviceCaps(LOGPIXELSX), dc.GetDeviceCaps(LOGPIXELSY));
dc.DPtoLP(&recPrint);
dc.SetWindowOrg(0, 0);

CFont newFont;
VERIFY(newFont.CreatePointFont(120, _T("宋体"), &dc));
CFont* oldFont = dc.SelectObject(&newFont);

dc.SetTextAlign(TA_TOP | TA_LEFT);

CString strPrint;
int nIndex = 0;
int x = 50;
int y = 50;
CSize textSize;
textSize = dc.GetTextExtent(_T("00"), 2);							//根据当前字体的宽、高，后面以此高度为行高

while ((nIndex = strMessage.Find(_T("\r\n"))) > -1)					//将IDC_EDIT1编辑框中内容打印，支持换行，一次换行等于'\r\n'，所以在开头strMessage += _T("\r\n")
{
	strPrint = strMessage.Left(nIndex);
	strMessage = strMessage.Mid(nIndex+2);

	dc.TextOutW(x, y, strPrint);

	y += textSize.cy;												//下移一行，行高为字体高度
}

dc.SelectObject(oldFont);
newFont.DeleteObject();
dc.EndPage();
dc.EndDoc();
DeleteDC(dc.Detach());

关于GetPrinterDevice，来自微软的一篇文章，点我跳转
代码也贴出来

BOOL CMFCApplication2Dlg::GetPrinterDevice(LPTSTR pszPrinterName, HGLOBAL* phDevNames, HGLOBAL* phDevMode)
{
	// if NULL is passed, then assume we are setting app object's
	// devmode and devnames
	if (phDevMode == NULL || phDevNames == NULL)
		return FALSE;
 
// Open printer
HANDLE hPrinter;
if (OpenPrinter(pszPrinterName, &hPrinter, NULL) == FALSE)
	return FALSE;

// obtain PRINTER_INFO_2 structure and close printer
DWORD dwBytesReturned, dwBytesNeeded;
GetPrinter(hPrinter, 2, NULL, 0, &dwBytesNeeded);
PRINTER_INFO_2* p2 = (PRINTER_INFO_2*)GlobalAlloc(GPTR,
	dwBytesNeeded);
if (GetPrinter(hPrinter, 2, (LPBYTE)p2, dwBytesNeeded,
	&dwBytesReturned) == 0) {
		GlobalFree(p2);
		ClosePrinter(hPrinter);
		return FALSE;
}
ClosePrinter(hPrinter);

// Allocate a global handle for DEVMODE
HGLOBAL  hDevMode = GlobalAlloc(GHND, sizeof(*p2->pDevMode) +
	p2->pDevMode->dmDriverExtra);
ASSERT(hDevMode);
DEVMODE* pDevMode = (DEVMODE*)GlobalLock(hDevMode);
ASSERT(pDevMode);

// copy DEVMODE data from PRINTER_INFO_2::pDevMode
memcpy(pDevMode, p2->pDevMode, sizeof(*p2->pDevMode) +
	p2->pDevMode->dmDriverExtra);
GlobalUnlock(hDevMode);

// Compute size of DEVNAMES structure from PRINTER_INFO_2's data
DWORD drvNameLen = lstrlen(p2->pDriverName)+1;  // driver name
DWORD ptrNameLen = lstrlen(p2->pPrinterName)+1; // printer name
DWORD porNameLen = lstrlen(p2->pPortName)+1;    // port name

// Allocate a global handle big enough to hold DEVNAMES.
HGLOBAL hDevNames = GlobalAlloc(GHND,
	sizeof(DEVNAMES) +
	(drvNameLen + ptrNameLen + porNameLen)*sizeof(TCHAR));
ASSERT(hDevNames);
DEVNAMES* pDevNames = (DEVNAMES*)GlobalLock(hDevNames);
ASSERT(pDevNames);

// Copy the DEVNAMES information from PRINTER_INFO_2
// tcOffset = TCHAR Offset into structure
int tcOffset = sizeof(DEVNAMES)/sizeof(TCHAR);
ASSERT(sizeof(DEVNAMES) == tcOffset*sizeof(TCHAR));

pDevNames->wDriverOffset = tcOffset;
memcpy((LPTSTR)pDevNames + tcOffset, p2->pDriverName,
	drvNameLen*sizeof(TCHAR));
tcOffset += drvNameLen;

pDevNames->wDeviceOffset = tcOffset;
memcpy((LPTSTR)pDevNames + tcOffset, p2->pPrinterName,
	ptrNameLen*sizeof(TCHAR));
tcOffset += ptrNameLen;

pDevNames->wOutputOffset = tcOffset;
memcpy((LPTSTR)pDevNames + tcOffset, p2->pPortName,
	porNameLen*sizeof(TCHAR));
pDevNames->wDefault = 0;

GlobalUnlock(hDevNames);
GlobalFree(p2);   // free PRINTER_INFO_2

// set the new hDevMode and hDevNames
*phDevMode = hDevMode;
*phDevNames = hDevNames;
return TRUE;

}