Question

我有一个DLL Com Server，实际上只使用一个旧的Delphi exe-application。

COM Server是多年前（不是我）在C ++ ATL中编写的。它实现了回调（事件 - 是否相同？） - 使用传出接口IConnectionPointImpl。类工厂是单件（标有DECLARE_CLASSFACTORY_SINGLETON）

现在需要在多个客户端之间共享此COM服务器：Delphi和C＃（.NET 2.0，VS2008）。我把它作为DllSurrogate，现在我可以从多个Delphi客户端使用它，使用继承自TOleServer的类，重写GetServer方法始终使用CoCreateInstance（因为{{1}通常都会失败）而且它正在发挥作用。

现在我需要从C＃WinService中使用它，我不知道从哪里开始。我写了一个使用WinApi GetActiveObject和CoCreateInstance的小C＃Hello-world - 我能够从COM Server连接到现有实例，但无法订阅事件。

这是VS导入的DLL META-DATA： enter image description here

我不知道这是否正确。这是近似代码：

DllImport("ole32.dll")

欢迎任何建议，链接和诀窍。

Answer 1

似乎我成功连接到并处理DLL（进程内）Com Server的事件。

我将COM Server作为DLL代理（HowTo here）。
Delphi客户端 - 构成我的COM Wrapper类，继承自TOleServer Class I重写GetServer方法：

function TSWMgr.GetServer: IUnknown; begin OleCheck(CoCreateInstance(ServerData^.ClassId, nil, CLSCTX_LOCAL_SERVER, IUnknown, Result)); end;

C＃（Hello-World Client）方面（在咨询了this之类的HowTos之后）：

//使用SWLMLib; //使用System.Runtime.InteropServices; //使用System.Runtime.InteropServices.ComTypes;

[Flags]
enum ReturnCode : uint
{
    S_OK = 0, S_FALSE = 1, REGDB_E_CLASSNOTREG = 0x80040154, CLASS_E_NOAGGREGATION = 0x80040110, E_NOINTERFACE = 0x80004002, E_POINTER = 0x80004003
}

[Flags]
enum CLSCTX : uint
{
    CLSCTX_INPROC_SERVER = 0x1, CLSCTX_INPROC_HANDLER = 0x2, CLSCTX_LOCAL_SERVER = 0x4,
    //... //others
    CLSCTX_ALL = CLSCTX_SERVER | CLSCTX_INPROC_HANDLER
}

/// <summary>
/// Sink Class implementig COM Server outgoing interface SWLMLib.ISWMgrEvents 
/// </summary>
[ClassInterface(ClassInterfaceType.None)]
class MySink : SWLMLib.ISWMgrEvents
{
    public void FeatureAboutToExpire(SWLMLib.IFeature pFeature, int HoursRemained)
    {
        Console.WriteLine("{0} FeatureAboutToExpire: Feature {1} Hours={2}", DateTime.Now, pFeature.Code, HoursRemained);
        Marshal.ReleaseComObject(pFeature); //WTF??? Without this line COM Server object is not released!
    }

    public void FeatureExpired(SWLMLib.IFeature pFeature)
    {
        Console.WriteLine("FeatureExpired: Feature {0}", pFeature.Code);
        Marshal.ReleaseComObject(pFeature); //Without this line COM Server object is not released!
    }
}

class Program
{
    //Import "CoCreateInstance" to play with run context of created COM-object (3rd parameter)
    [DllImport("ole32.dll", EntryPoint = "CoCreateInstance", CallingConvention = CallingConvention.StdCall)]
    static extern UInt32 CoCreateInstance([In, MarshalAs(UnmanagedType.LPStruct)] Guid rclsid,
       IntPtr pUnkOuter, UInt32 dwClsContext, [In, MarshalAs(UnmanagedType.LPStruct)] Guid riid,
       [MarshalAs(UnmanagedType.IUnknown)] out object rReturnedComObject);

    static void Main(string[] args)
    {
        try
        {
            Guid SWMgrClassObjectGuid = typeof(SWLMLib.SWMgrClass).GUID;    //{8EAAFAD7-73F8-403B-A53B-4400E16D8EDF}
            Guid IUnknownGuid = new Guid("00000000-0000-0000-C000-000000000046"); //Can it be written in more pretty style?

            SWLMLib.ISWMgr lintfSWLMgr = null;

            /* This will create IN-PROC Server because, it seems CoCreateInstance will be invoked with CLSCTX_INPROC_SERVER flag settled
            Type type = Type.GetTypeFromCLSID(SWMgrClassObjectGuid), true);
            object instance0 = Activator.CreateInstance(type);
            lintfSWLMgr = (instance0 as SWLMLib.ISWMgr); */

            Guid Ev1 = typeof(ISWMgrEvents).GUID;
            object instance = null;

            unsafe
            {
                UInt32 dwRes = CoCreateInstance(SWMgrClassObjectGuid,
                                                IntPtr.Zero,
                                                (uint)(CLSCTX.CLSCTX_LOCAL_SERVER), //if OR with CLSCTX_INPROC_SERVER then INPROC Server will be created, because of DLL COM Server
                                                IUnknownGuid,
                                                out instance);
                if (dwRes != 0)
                {
                    int iError = Marshal.GetLastWin32Error();
                    Console.WriteLine("CoCreateInstance Error = {0}, LastWin32Error = {1}", dwRes, iError);
                    return;
                }
                lintfSWLMgr = (instance as SWLMLib.ISWMgr);
            }

            if (lintfSWLMgr != null)
            {
                //lintfSWLMgr.InitializeMethod(...); //Initialize object

                //Find Connection Point for Events
                Guid ISWMgrEventsGuid = typeof(SWLMLib.ISWMgrEvents).GUID;      //{C13A9D38-4BB0-465B-BF4A-487F371A5538} Interface for Evenets Handling
                IConnectionPoint lCP = null;
                IConnectionPointContainer lCPC = (instance as IConnectionPointContainer);
                lCPC.FindConnectionPoint(ref ISWMgrEventsGuid, out lCP);

                MySink lSink = new MySink();
                Int32 dwEventsCookie;
                lCP.Advise(lSink, out dwEventsCookie);
                Console.WriteLine("Waiting for Events Handling...");
                Console.WriteLine("Press ENTER to Exit...");

                Console.ReadLine(); // Until Eneter is not hit, the events arrive properly
                //Here starting to Unsubscribe for Events and Com Objects CleanUP
                lCP.Unadvise(dwEventsCookie);
                Marshal.ReleaseComObject(lCP); 
                Marshal.ReleaseComObject(lintfSWLMgr); 
            }

        }
        catch (Exception E)
        {
            Console.WriteLine(E.Message);
            throw;
        }
    }
}

也许这不是最好的方式（比如TblImp.exe和/或COM Wrappers），但这种原始方式有效。

Answer 2

我想你会想要编写如下代码：

Type type = Type.GetTypeFromCLSID(coClassGuid, true);
object instance = Activator.CreateInstance(type);

您可以将此视为与CoCreateInstance类似。

执行QueryInterface的C＃COM Interop方式是进行转换或使用as关键字：

IComInterface comInterface = instance as IComInterface;

这将避免您必须直接使用COM API。

我绝不是COM Interop专家，我只需要做一些工作，所以我希望这可以帮助你。

如何在.NET C＃WinService中使用COM服务器（ATL，DLL代理）？

2 个答案: