C# - 可以使用 IOCTL

Question

我正在尝试为允许“现金抽屉”附件的销售点系统编写代码。打开现金抽屉的手册中提供了代码(使用 IOCTL 在 C++ 中)。由于我在 C# .NET 中编码，是否可以在 C# 中执行类似的操作，或者我是否必须编写一些非托管代码？

我能否从 C# 中获取“\\.\ADVANSYS”的句柄？我需要使用 DLLImport 吗？

如果有人能指出正确的方向，我将不胜感激。

// IOCTL Codes
#define GPD_TYPE 56053
#define ADV_OPEN_CTL_CODE CTL_CODE(GPD_TYPE, 0x920, METHOD_BUFFERED, FILE_ANY_ACCESS)
#define ADV_STATUS_CTL_CODE CTL_CODE(GPD_TYPE, 0x900, METHOD_BUFFERED, FILE_ANY_ACCESS)
void OpenDrawer(UCHAR uWhichDrawer) // uWhichDrawer = 1 => CD#1, uWhichDrawer = 2 => CD#2
{
    HANDLE hFile;
    BOOL bRet
    UCHAR uDrawer = uWhichDrawer;

    // Open the driver
    hFile = CreateFile(TEXT("\\\\.\\ADVSYS"),
    GENERIC_WRITE | GENERIC_READ,
    FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
    OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

    if (m_hFile == INVALID_HANDLE_VALUE)
    {
        AfxMessageBox("Unable to open Cash Drawer Device Driver!");
        return;
    }

    // Turn on the Cash Drawer Output (Fire the required solenoid)
    bRet = DeviceIoControl(hFile, ADV_CD_OPEN_CTL_CODE,
    &uDrawer, sizeof(uDrawer),
    NULL, 0,
    &ulBytesReturned, NULL);

    if (bRet == FALSE || ulBytesReturned != 1)
    {
        AfxMessageBox("Failed to write to cash drawer driver");
        CloseHandle(hFile);
        return;
    }
    CloseHandle(hFile);
}

Answer 1

C++ 错误百出，不确定我是否正确。最好的办法是使用更改后的参数类型声明 DeviceIoControl()，以便于调用。您还必须 P/Invoke CreateFile 因为 FileStream 无法打开设备。它应该看起来像这样:

using System;
using System.IO;
using System.ComponentModel;
using System.Runtime.InteropServices;

class Program {
    static void Main(string[] args) {
        IntPtr hdl = CreateFile("\\\\.\\ADVSYS", FileAccess.ReadWrite,
            FileShare.None, IntPtr.Zero, FileMode.Open,
            FileOptions.None, IntPtr.Zero);
        if (hdl == (IntPtr)(-1)) throw new Win32Exception();
        try {
            byte drawer = 1;
            bool ok = DeviceIoControl(hdl, CTLCODE, ref drawer, 1, IntPtr.Zero,
                0, IntPtr.Zero, IntPtr.Zero);
            if (!ok) throw new Win32Exception();
        }
        finally {
            CloseHandle(hdl);
        }
    }
    // P/Invoke:
    private const uint CTLCODE = 0xdaf52480;
    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr CreateFile(string filename, FileAccess access,
          FileShare sharing, IntPtr SecurityAttributes, FileMode mode,
          FileOptions options, IntPtr template
    );
    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool DeviceIoControl(IntPtr device, uint ctlcode,
        ref byte inbuffer, int inbuffersize,
        IntPtr outbuffer, int outbufferSize,
        IntPtr bytesreturned, IntPtr overlapped
    );
    [DllImport("kernel32.dll")]
    private static extern void CloseHandle(IntPtr hdl);
}