问题描述
我的目标是使用 CreateFile 打开通过 USB 连接的打印机(然后发出一些 WriteFiles 和 ReadFiles).
My goal is to open a printer connected via USB using the CreateFile (and then issue some WriteFiles and ReadFiles).
如果打印机是 LPT 打印机，我会简单地执行 CreateFile("LPT1:", ...).但是对于 USB 打印机，必须将一个特殊的设备路径传递给 CreateFile 才能打开该打印机.
If the printer was an LPT one, I would simply do CreateFile("LPT1:", ...). But for USB printers, there is a special device path that must be passed to CreateFile in order to open that printer.
这个设备路径，因为我能找到，通过 SetupDiGetClassDevs 检索代码> -> SetupDiEnumDeviceInterfaces -> SetupDiGetDeviceInterfaceDetail -> DevicePath成员，看起来像这样:
This device path, as I was able to find, is retrieved via SetupDiGetClassDevs -> SetupDiEnumDeviceInterfaces -> SetupDiGetDeviceInterfaceDetail -> DevicePath member and looks like this:
\\?\usb#vid_0a5f&pid_0027#46a072900549#{28d78fad-5a12-11d1-ae5b-0000f803a8c2}
一切都很好，但我输入的是可读的打印机名称，如设备和打印机所示.SetupDi* 函数似乎没有使用它，它们只在 设备实例 ID.所以现在的问题是如何从打印机名称中获取设备实例 ID，它会传递给 OpenPrinter.
All that is fine, but what I have as the input is the human-readable printer name, as seen in Devices and Printers. The SetupDi* functions don't seem to use that, they only operate on device instance IDs. So the question is now how to get device instance ID from the printer name one would pass to OpenPrinter.
不难看出，上面的GUID部分是GUID_DEVINTERFACE_USBPRINT，而\\?\usb是固定的，所以唯一的一点我是真的感兴趣的是vid_0a5f&pid_0027#46a072900549#.我可以在打印机属性对话框中轻松手动查找此路径:
It's not difficult to observe that the GUID part of the above is the GUID_DEVINTERFACE_USBPRINT, and \\?\usb is fixed, so the only bit I'm really interested in is vid_0a5f&pid_0027#46a072900549#. This path I can easily look up manually in the printer properties dialog:
转到设备和打印机
右键单击打印机
属性
切换到硬件选项卡
选择打印设备，例如 ZDesigner LP2844-Z
属性
切换到详细信息选项卡
从下拉菜单中选择家长".
但我不知道如何以编程方式执行此操作，前提是给出的唯一内容是设备和打印机"面板中显示的打印机名称.
But I have no idea how to do that programmatically provided the only thing given is the printer name as seen in the Device and Printers panel.
附言1:我对使用 OpenPrinter 打开打印机然后使用 WritePrinter/ReadPrinter 不感兴趣.已经完成，效果很好，但现在目标不同了.
P.S. 1: I'm not interested in opening the printer with OpenPrinter and then using WritePrinter / ReadPrinter. That has been done, works fine, but now the goal is different.
附言2:我可以用更简单的方法将可读的打印机名称转换为可以传递给 CreateFile 的内容.
P.S. 2: I'll be OK with a simpler way to convert the readable printer name to something that can be passed to CreateFile.
附言3:这个问题，我已经发布了一个答案，与我最终想做的事情非常相关.
P.S. 3: This question, to which I have posted an answer, is very related to what I ultimately want to do.
附言4:反过来也可以:如果可以从SP_DEVINFO_DATA 结构，这也是答案，虽然不太方便.
P.S. 4: The other way round is also fine: If it is possible to obtain the readable name from the SP_DEVINFO_DATA structure, that will also be the answer, although a less convenient one.
推荐答案
以下是我终于能够想出的.
Below is what I finally have been able to come up with.
请确认SYSTEM\CurrentControlSet\Control\Print\Printers\{0}\PNPData 是受支持的路径，而不仅仅是当前实施，未来可能会发生变化.
Please confirm that SYSTEM\CurrentControlSet\Control\Print\Printers\{0}\PNPData is a supported path, and not just happens to be there in the current implementation, subject to future changes.
结构对齐有一个小问题，为此我发布了一个单独的问题.
There's a little problem with structure alignment, for which I've posted a separate question.
public static class UsbPrinterResolver
{
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
private struct SP_DEVINFO_DATA
{
public uint cbSize;
public Guid ClassGuid;
public uint DevInst;
public IntPtr Reserved;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
private struct SP_DEVICE_INTERFACE_DATA
{
public uint cbSize;
public Guid InterfaceClassGuid;
public uint Flags;
public IntPtr Reserved;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto, Pack = 1)]
private struct SP_DEVICE_INTERFACE_DETAIL_DATA // Only used for Marshal.SizeOf. NOT!
{
public uint cbSize;
public char DevicePath;
}
[DllImport("cfgmgr32.dll", CharSet = CharSet.Auto, SetLastError = false, ExactSpelling = true)]
private static extern uint CM_Get_Parent(out uint pdnDevInst, uint dnDevInst, uint ulFlags);
[DllImport("cfgmgr32.dll", CharSet = CharSet.Auto, SetLastError = false)]
private static extern uint CM_Get_Device_ID(uint dnDevInst, string Buffer, uint BufferLen, uint ulFlags);
[DllImport("cfgmgr32.dll", CharSet = CharSet.Auto, SetLastError = false, ExactSpelling = true)]
private static extern uint CM_Get_Device_ID_Size(out uint pulLen, uint dnDevInst, uint ulFlags);
[DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr SetupDiGetClassDevs([In(), MarshalAs(UnmanagedType.LPStruct)] System.Guid ClassGuid, string Enumerator, IntPtr hwndParent, uint Flags);
[DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern int SetupDiEnumDeviceInfo(IntPtr DeviceInfoSet, uint MemberIndex, ref SP_DEVINFO_DATA DeviceInfoData);
[DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern int SetupDiEnumDeviceInterfaces(IntPtr DeviceInfoSet, [In()] ref SP_DEVINFO_DATA DeviceInfoData, [In(), MarshalAs(UnmanagedType.LPStruct)] System.Guid InterfaceClassGuid, uint MemberIndex, ref SP_DEVICE_INTERFACE_DATA DeviceInterfaceData);
[DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern int SetupDiGetDeviceInterfaceDetail(IntPtr DeviceInfoSet, [In()] ref SP_DEVICE_INTERFACE_DATA DeviceInterfaceData, IntPtr DeviceInterfaceDetailData, uint DeviceInterfaceDetailDataSize, out uint RequiredSize, IntPtr DeviceInfoData);
[DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]
private static extern int SetupDiDestroyDeviceInfoList(IntPtr DeviceInfoSet);
[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
private static extern IntPtr CreateFile(string lpFileName, uint dwDesiredAccess, int dwShareMode, IntPtr lpSecurityAttributes, int dwCreationDisposition, int dwFlagsAndAttributes, IntPtr hTemplateFile);
private const uint DIGCF_PRESENT = 0x00000002U;
private const uint DIGCF_DEVICEINTERFACE = 0x00000010U;
private const int ERROR_INSUFFICIENT_BUFFER = 122;
private const uint CR_SUCCESS = 0;
private const int FILE_SHARE_READ = 1;
private const int FILE_SHARE_WRITE = 2;
private const uint GENERIC_READ = 0x80000000;
private const uint GENERIC_WRITE = 0x40000000;
private const int OPEN_EXISTING = 3;
private static readonly Guid GUID_PRINTER_INSTALL_CLASS = new Guid(0x4d36e979, 0xe325, 0x11ce, 0xbf, 0xc1, 0x08, 0x00, 0x2b, 0xe1, 0x03, 0x18);
private static readonly Guid GUID_DEVINTERFACE_USBPRINT = new Guid(0x28d78fad, 0x5a12, 0x11D1, 0xae, 0x5b, 0x00, 0x00, 0xf8, 0x03, 0xa8, 0xc2);
private static readonly IntPtr INVALID_HANDLE_VALUE = new IntPtr(-1);
private static string GetPrinterRegistryInstanceID(string PrinterName) {
if (string.IsNullOrEmpty(PrinterName)) throw new ArgumentNullException("PrinterName");
const string key_template = @"SYSTEM\CurrentControlSet\Control\Print\Printers\{0}\PNPData";
using (var hk = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(
string.Format(key_template, PrinterName),
Microsoft.Win32.RegistryKeyPermissionCheck.Default,
System.Security.AccessControl.RegistryRights.QueryValues
)
)
{
if (hk == null) throw new ArgumentOutOfRangeException("PrinterName", "This printer does not have PnP data.");
return (string)hk.GetValue("DeviceInstanceId");
}
}
private static string GetPrinterParentDeviceId(string RegistryInstanceID) {
if (string.IsNullOrEmpty(RegistryInstanceID)) throw new ArgumentNullException("RegistryInstanceID");
IntPtr hdi = SetupDiGetClassDevs(GUID_PRINTER_INSTALL_CLASS, RegistryInstanceID, IntPtr.Zero, DIGCF_PRESENT);
if (hdi.Equals(INVALID_HANDLE_VALUE)) throw new System.ComponentModel.Win32Exception();
try
{
SP_DEVINFO_DATA printer_data = new SP_DEVINFO_DATA();
printer_data.cbSize = (uint)Marshal.SizeOf(typeof(SP_DEVINFO_DATA));
if (SetupDiEnumDeviceInfo(hdi, 0, ref printer_data) == 0) throw new System.ComponentModel.Win32Exception(); // Only one device in the set
uint cmret = 0;
uint parent_devinst = 0;
cmret = CM_Get_Parent(out parent_devinst, printer_data.DevInst, 0);
if (cmret != CR_SUCCESS) throw new Exception(string.Format("Failed to get parent of the device '{0}'. Error code: 0x{1:X8}", RegistryInstanceID, cmret));
uint parent_device_id_size = 0;
cmret = CM_Get_Device_ID_Size(out parent_device_id_size, parent_devinst, 0);
if (cmret != CR_SUCCESS) throw new Exception(string.Format("Failed to get size of the device ID of the parent of the device '{0}'. Error code: 0x{1:X8}", RegistryInstanceID, cmret));
parent_device_id_size++; // To include the null character
string parent_device_id = new string('\0', (int)parent_device_id_size);
cmret = CM_Get_Device_ID(parent_devinst, parent_device_id, parent_device_id_size, 0);
if (cmret != CR_SUCCESS) throw new Exception(string.Format("Failed to get device ID of the parent of the device '{0}'. Error code: 0x{1:X8}", RegistryInstanceID, cmret));
return parent_device_id;
}
finally
{
SetupDiDestroyDeviceInfoList(hdi);
}
}
private static string GetUSBInterfacePath(string SystemDeviceInstanceID) {
if (string.IsNullOrEmpty(SystemDeviceInstanceID)) throw new ArgumentNullException("SystemDeviceInstanceID");
IntPtr hdi = SetupDiGetClassDevs(GUID_DEVINTERFACE_USBPRINT, SystemDeviceInstanceID, IntPtr.Zero, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
if (hdi.Equals(INVALID_HANDLE_VALUE)) throw new System.ComponentModel.Win32Exception();
try
{
SP_DEVINFO_DATA device_data = new SP_DEVINFO_DATA();
device_data.cbSize = (uint)Marshal.SizeOf(typeof(SP_DEVINFO_DATA));
if (SetupDiEnumDeviceInfo(hdi, 0, ref device_data) == 0) throw new System.ComponentModel.Win32Exception(); // Only one device in the set
SP_DEVICE_INTERFACE_DATA interface_data = new SP_DEVICE_INTERFACE_DATA();
interface_data.cbSize = (uint)Marshal.SizeOf(typeof(SP_DEVICE_INTERFACE_DATA));
if (SetupDiEnumDeviceInterfaces(hdi, ref device_data, GUID_DEVINTERFACE_USBPRINT, 0, ref interface_data) == 0) throw new System.ComponentModel.Win32Exception(); // Only one interface in the set
// Get required buffer size
uint required_size = 0;
SetupDiGetDeviceInterfaceDetail(hdi, ref interface_data, IntPtr.Zero, 0, out required_size, IntPtr.Zero);
int last_error_code = Marshal.GetLastWin32Error();
if (last_error_code != ERROR_INSUFFICIENT_BUFFER) throw new System.ComponentModel.Win32Exception(last_error_code);
IntPtr interface_detail_data = Marshal.AllocCoTaskMem((int)required_size);
try
{
// FIXME, don't know how to calculate the size.
// See https://stackoverflow.com/questions/10728644/properly-declare-sp-device-interface-detail-data-for-pinvoke
switch (IntPtr.Size)
{
case 4:
Marshal.WriteInt32(interface_detail_data, 4 + Marshal.SystemDefaultCharSize);
break;
case 8:
Marshal.WriteInt32(interface_detail_data, 8);
break;
default:
throw new NotSupportedException("Architecture not supported.");
}
if (SetupDiGetDeviceInterfaceDetail(hdi, ref interface_data, interface_detail_data, required_size, out required_size, IntPtr.Zero) == 0) throw new System.ComponentModel.Win32Exception();
// TODO: When upgrading to .NET 4, replace that with IntPtr.Add
return Marshal.PtrToStringAuto(new IntPtr(interface_detail_data.ToInt64() + Marshal.OffsetOf(typeof(SP_DEVICE_INTERFACE_DETAIL_DATA), "DevicePath").ToInt64()));
}
finally
{
Marshal.FreeCoTaskMem(interface_detail_data);
}
}
finally
{
SetupDiDestroyDeviceInfoList(hdi);
}
}
public static string GetUSBPath(string PrinterName) {
return GetUSBInterfacePath(GetPrinterParentDeviceId(GetPrinterRegistryInstanceID(PrinterName)));
}
public static Microsoft.Win32.SafeHandles.SafeFileHandle OpenUSBPrinter(string PrinterName) {
return new Microsoft.Win32.SafeHandles.SafeFileHandle(CreateFile(GetUSBPath(PrinterName), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero, OPEN_EXISTING, 0, IntPtr.Zero), true);
}
}
用法:
using (var sh = UsbPrinterResolver.OpenUSBPrinter("Zebra Large"))
{
using (var f = new System.IO.FileStream(sh, System.IO.FileAccess.ReadWrite))
{
// Read from and write to the stream f
}
}
这篇关于确定哪个打印机名称对应哪个设备 ID的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！