我如何注册' IPrintAsyncNotifyCallback '从c#

本文关键字：IPrintAsyncNotifyCallback 何注册注册 | 更新日期: 2023-09-27 18:16:46

我正在尝试从v3打印机驱动程序或端口监视器接收回调，但希望从c#这样做。文档说，我们应该能够只是传递一个对象实现IPrintAsyncNotifyCallback到RegisterForPrintAsyncNotifications，并有一个例子在c++中，但我找不到一个TLB能够在c#中实现这个接口。

此外，RegisterForPrintAsyncNotifications似乎没有从文档(Spoolss.dll)中命名的dll中导出。

我如何实现IPrintAsyncNotifyCallback没有TLB?如何定位RegisterForPrintAsyncNotifications ?

首先，考虑编写v4打印驱动程序。虽然v3驱动程序支持不太可能很快被放弃，但v4驱动程序肯定是新开发的必经之路。它们还具有用于回调的. net API，从而避免了必须自己编写互操作。参见PrinterExtensionSample .

实现不带TLB的COM接口

为了实现IPrintAsyncNotifyCallback及其引用的IPrintAsyncNotifyChannel和IPrintAsyncNotifyDataObject接口，我们可以在下面的prnasnot.h中找到它们的定义。

// ... snip ...
DEFINE_GUID(IID_IPrintAsyncNotifyChannel,        0x4a5031b1, 0x1f3f, 0x4db0, 0xa4, 0x62, 0x45, 0x30, 0xed, 0x8b, 0x04, 0x51);
DEFINE_GUID(IID_IPrintAsyncNotifyCallback,       0x7def34c1, 0x9d92, 0x4c99, 0xb3, 0xb3, 0xdb, 0x94, 0xa9, 0xd4, 0x19, 0x1b);
DEFINE_GUID(IID_IPrintAsyncNotifyDataObject,     0x77cf513e, 0x5d49, 0x4789, 0x9f, 0x30, 0xd0, 0x82, 0x2b, 0x33, 0x5c, 0x0d);
// ... snip ...
DECLARE_INTERFACE_(IPrintAsyncNotifyDataObject, IUnknown)
{
    // ... snip ...
};
// ... snip ...
DECLARE_INTERFACE_(IPrintAsyncNotifyChannel, IUnknown)
{
    // ... snip ...
};
// ... snip ...
DECLARE_INTERFACE_(IPrintAsyncNotifyCallback, IUnknown)
{
    STDMETHOD(QueryInterface)(
        THIS_
        _In_        REFIID riid,
        _Outptr_ void   **ppvObj
        ) PURE;
    STDMETHOD_(ULONG, AddRef)(
        THIS
        ) PURE;
    STDMETHOD_(ULONG, Release)(
        THIS
        ) PURE;
    STDMETHOD(OnEventNotify)(
         THIS_
         _In_ IPrintAsyncNotifyChannel    *pChannel,
         _In_ IPrintAsyncNotifyDataObject *pData
         ) PURE;
    STDMETHOD(ChannelClosed)(
         THIS_
         _In_ IPrintAsyncNotifyChannel    *pChannel,
         _In_ IPrintAsyncNotifyDataObject *pData
         ) PURE;
};

顶部的IID s以及方法排序和签名允许我们将其转换为适当的ComImport s。

[ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("77cf513e-5d49-4789-9f30-d0822b335c0d")]
public interface IPrintAsyncNotifyDataObject
{
    void AcquireData(out IntPtr data, out uint cbData, out IntPtr schema);
    void ReleaseData();
}
[ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("4a5031b1-1f3f-4db0-a462-4530ed8b0451")]
public interface IPrintAsyncNotifyChannel
{
    void SendNotification(IPrintAsyncNotifyDataObject data);
    void CloseChannel(IPrintAsyncNotifyDataObject data);
}
[ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("7def34c1-9d92-4c99-b3b3-db94a9d4191b")]
public interface IPrintAsyncNotifyCallback
{
    void OnEventNotify(IPrintAsyncNotifyChannel channel, IPrintAsyncNotifyDataObject data);
    void ChannelClosed(IPrintAsyncNotifyChannel channel, IPrintAsyncNotifyDataObject data);
}
public enum PrintAsyncNotifyUserFilter : uint
{
    kPerUser = 0,
    kAllUsers = 1
}
public enum PrintAsyncNotifyConversationStyle : uint
{
    kBiDirectional = 0,
    kUniDirectional = 1
}

<标题>发现RegisterForPrintAsyncNotifications h1> 于c++示例按原样工作，并且RegisterForPrintAsyncNotifications是一个import –而不是一个宏& &;链接器将查看文档中命名的WinSpool.lib文件，以找到适当的dll。我们可以使用dumpbin做同样的事情。

c:'Drop>dumpbin -headers "C:'Program Files (x86)'Windows Kits'10'Lib'10.0.10586.0'um'x64'WinSpool.Lib" > out.txt
// ... snip ...
  Version      : 0
  Machine      : 8664 (x64)
  TimeDateStamp: 56F9F510 Mon Mar 28 22:22:56 2016
  SizeOfData   : 00000030
  DLL name     : WINSPOOL.DRV
  Symbol name  : RegisterForPrintAsyncNotifications
  Type         : code
  Name type    : name
  Hint         : 162
  Name         : RegisterForPrintAsyncNotifications
// ... snip ...

显示RegisterForPrintAsyncNotifications实际上是从WINSPOOL.DRV导出的。

[DllImport("WINSPOOL.DRV", PreserveSig = false, ExactSpelling = true)]
public static extern void RegisterForPrintAsyncNotifications(
    [MarshalAs(UnmanagedType.LPWStr)] string name,
    [MarshalAs(UnmanagedType.LPStruct)] Guid notificationType, PrintAsyncNotifyUserFilter filter,
    PrintAsyncNotifyConversationStyle converstationStyle,
    IPrintAsyncNotifyCallback callback, out PrintAsyncNotificationSafeHandle handle);
[DllImport("WINSPOOL.DRV", PreserveSig = true, ExactSpelling = true)]
public static extern int UnRegisterForPrintAsyncNotifications(IntPtr handle);
public sealed class PrintAsyncNotificationSafeHandle : SafeHandleZeroOrMinusOneIsInvalid
{
    public PrintAsyncNotificationSafeHandle()
        : base(true)
    {
    }
    protected override bool ReleaseHandle()
    {
        return UnRegisterForPrintAsyncNotifications(handle) == 0 /* S_OK */;
    }
}