這段實在很重要，對於VB6的程式來說，要開錢櫃，在有接發票機的情形下，直接輸出LPT即可，，沒有發票機時只能透過熱感式出單機協助。但現在有些熱感式出單機是網路型的，直接輸出LPT就沒用了。
所以，當你的電腦接網路，網路接出單機，而出單機再接錢櫃時，下列的範例就是很好用的C#程式，以我的狀況是，用C#寫一支下列程式，呼叫下面這個Class，打開錢櫃後就自動結束程式；接著在VB6呼叫這隻程式，就可以很開心的在沒有發票機的狀況下打開錢櫃啦~
PS:很抱歉，這段資料的來源我忘了保留下來了，如果有人知道，也可以告訴我，我會立即補上出處的，感謝~
using System;
using System.Drawing;
using System.Drawing.Printing;
using System.IO;
using System.Windows.Forms;
using System.Runtime.InteropServices;
class RawPrinterHelper
{
// Structure and API declarions:
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public class DOCINFOA
{
[MarshalAs(UnmanagedType.LPStr)]
public string pDocName;
[MarshalAs(UnmanagedType.LPStr)]
public string pOutputFile;
[MarshalAs(UnmanagedType.LPStr)]
public string pDataType;
}
[DllImport("winspool.Drv", EntryPoint = "OpenPrinterA", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool OpenPrinter([MarshalAs(UnmanagedType.LPStr)] string szPrinter, out IntPtr hPrinter, IntPtr pd);
[DllImport("winspool.Drv", EntryPoint = "ClosePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool ClosePrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "StartDocPrinterA", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool StartDocPrinter(IntPtr hPrinter, Int32 level, [In, MarshalAs(UnmanagedType.LPStruct)] DOCINFOA di);
[DllImport("winspool.Drv", EntryPoint = "EndDocPrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool EndDocPrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "StartPagePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool StartPagePrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "EndPagePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool EndPagePrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "WritePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool WritePrinter(IntPtr hPrinter, IntPtr pBytes, Int32 dwCount, out Int32 dwWritten);
// SendBytesToPrinter()
// When the function is given a printer name and an unmanaged array
// of bytes, the function sends those bytes to the print queue.
// Returns true on success, false on failure.
public static bool SendBytesToPrinter(string szPrinterName, IntPtr pBytes, Int32 dwCount)
{
Int32 dwError = 0, dwWritten = 0;
IntPtr hPrinter = new IntPtr(0);
DOCINFOA di = new DOCINFOA();
bool bSuccess = false; // Assume failure unless you specifically succeed.
di.pDocName = "My C#.NET RAW Document";
di.pDataType = "RAW";
// Open the printer.
if (OpenPrinter(szPrinterName.Normalize(), out hPrinter, IntPtr.Zero))
{
// Start a document.
if (StartDocPrinter(hPrinter, 1, di))
{
// Start a page.
if (StartPagePrinter(hPrinter))
{
// Write your bytes.
bSuccess = WritePrinter(hPrinter, pBytes, dwCount, out dwWritten);
EndPagePrinter(hPrinter);
}
EndDocPrinter(hPrinter);
}
ClosePrinter(hPrinter);
}
// If you did not succeed, GetLastError may give more information
// about why not.
if (bSuccess == false)
{
dwError = Marshal.GetLastWin32Error();
}
return bSuccess;
}
}
Then use the following method to open the cash drawer
private void openCashDrawer()
{
//下面這行請改成錢櫃的指令
byte[] codeOpenCashDrawer = new byte[] { 27, 112, 48, 55, 121 };
IntPtr pUnmanagedBytes = new IntPtr(0);
pUnmanagedBytes = Marshal.AllocCoTaskMem(5);
Marshal.Copy(codeOpenCashDrawer, 0, pUnmanagedBytes, 5);
//下面這行的第一個參數"EPSON xxxx" 請改成印表機名稱，名稱哦~~很方便的
RawPrinterHelper.SendBytesToPrinter("EPSON TM-T88V Receipt Invoice", pUnmanagedBytes, 5);
Marshal.FreeCoTaskMem(pUnmanagedBytes);
}
