静态非托管dll C＃包装和多线程，多域名

Question

早上好。

这是我的场景：我有一个第三方非托管foo.dll与自动快速回报设备交互，称之为FooDevice。我写了一个关于foo.dll的方法的包装器，称它为FooWrapper，并且用编组和一些锤子敲打我最终使其工作;如您所知，在使用DllImport时，所有暴露的方法都需要标记为static和extern foo.dll公开了一些方法和回调函数指针;当我尝试在不同的线程中同时连接两个设备时，当tryng钩住此回调函数时，包装会挂起。 我知道static stuff是线程共享的，所以我想为每个FooWrapper istances使用不同的AppDomain。 你认为这是做这种工作的正确方法吗？

这一点我FooWrapper的：

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)] 
    public delegate void FOO_EventHandlerFunc([In] UInt16 event_id, [In, Out] ref IntPtr data, [In] IntPtr param); 

    [SuppressUnmanagedCodeSecurity] 
    internal static class FOO 
    { 
     static FOO() 
     { 
      //... 
     } 

     /// 
     /// FOO_RegisterEventHandler 
     /// The FOO_RegisterEventHandler function registers an application-defined callback 
     /// function, which will subsequently be called for all FooDevice generated events. 
     /// 
     /// long FOO_RegisterEventHandler(FOO_EventHandlerFunc handler, BYTE evmask, LONG param); 
     /// 
     /// Parameters 
     /// handler 
     /// [in] Pointer to an application-defined callback function (see below). 
     /// evmask 
     /// [in] Specify which events to enable (see EnableEvents). 
     /// param 
     /// [in] An application-defined value to be passed to the callback function 
     /// 
     /// Return Values 
     /// If the function succeeds, the return value is zero. 
     /// If the function fails, the return value is nonzero. 
     /// 
     /// Remarks 
     /// The FOO_EventHandlerFunc type defines a pointer to a callback function, which must 
     /// comply with the following, where FOO_EventHandlerFunc is a placeholder for the 
     /// application-defined function name. 
     /// 
     /// void FOO_EventHandlerFunc(WORD event_id, LPVOID data, LONG param); 
     /// 
     /// Parameters 
     /// event_id 
     /// [in] Event index as specified by the FooDevice protocol. 
     /// data 
     /// [in] Event data. The type of data depends on event_id. 
     /// (See the event specifications for FooDevice). 
     /// param 
     /// The application-defined value passed during registration. 
     /// 
     /// Remarks 
     /// Avoid lengthy callback functions, since it will stall the underlying protocol, 
     /// thereby interrupting a steady communications flow. 
     /// FooDevice will only be generating events during operation. 
     /// That is - between FOO_LogIn and FOO_LogOut. 
     /// 
     ///The handler. 
     ///The evmask. 
     ///The param. 
     /// 
     [DllImport("foo.dll", CallingConvention = CallingConvention.Winapi, CharSet = CharSet.Ansi)] 
     public static extern UInt32 FOO_RegisterEventHandler([In] [MarshalAs(UnmanagedType.FunctionPtr)] FOO_EventHandlerFunc handler, [In] byte evmask, [In] IntPtr param); 

     /// 
     /// FOO_LogIn 
     /// The FOO_LogIn function opens FooDevice for normal operation. 
     /// 
     /// long FOO_LogIn(LPSTR oper, LPSTR datetime); 
     /// 
     /// Parameters 
     /// oper 
     /// [in] Pointer to a null-terminated string identifying the cashier. 
     /// The string can have any content, but a maximum of 50 characters will be used. 
     /// datetime 
     /// [in] Pointer to a null-terminated string indicating the current date and time. 
     /// The string must have 'YYYYMMDDhhmmss' format to take effect. 
     /// Return Values 
     /// If the function succeeds, the return value is zero. 
     /// If the function fails, the return value is nonzero. 
     /// 
     ///The oper. 
     ///The datetime. 
     /// 
     [DllImport("foo.dll", CallingConvention = CallingConvention.Winapi, CharSet = CharSet.Ansi)] 
     public static extern UInt32 FOO_LogIn([In] string oper, [In] string datetime); 

     //... and so on ... 
    } 
} 

您能否提供我的方式来istantiate正确FooWrapper超过一次（在相同或differente线程或应用程序域）？

谢谢你们。 干杯， Nando

Answer 1

我完全理解您的问题。这是我想尝试，选择一个适合你的特殊情况

1. 我会尝试联系Foo.dll的供应商，并得到一个版本是线程安全的选项。

2. 如果在DLL上调用方法不会影响性能（它们需要很少的时间），我会通过锁定，登录，设置状态，执行操作和注销每个调用来使包装器线程安全。这是一个干净的解决方案，可以稍后用线程安全的foo.dll或甚至是基于C＃的新实现来替换。这也很容易测试和维护。

3. 第三个麻烦但很容易的选择是将P/Invoke类封装器封装到可执行文件中，并为每个线程启动一个进程并使用远程处理与类封装器的实际实例进行通信。你可以使用ThreadId来确定哪个进程是针对哪个线程和独立的调用启动的。

希望这些选项之一有所帮助！