Delphi XE7动态虚拟通道新增接口注册失败及查询异常求助

Let’s break down actionable steps to fix your registration errors and interface compatibility problems, tailored to your RDP Dynamic Virtual Channel (DVC) scenario:

1. Fix Manual Registration Gaps #

Your manual registry edits were a good start, but you might have missed critical details:

• Validate GUID Consistency: Double-check that the IID of your new interface matches exactly across your .idl file, Delphi implementation, and registry entries (case doesn’t matter, but consistency avoids silent failures).
• Complete Interface Registry Entries: For your new interface’s GUID key (under HKEY_CLASSES_ROOT\Interface\{YOUR_NEW_IID} and HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{YOUR_NEW_IID}—don’t forget the Wow6432Node path for 32-bit DLLs on 64-bit Windows), ensure you have:
  • A (Default) value set to your interface’s friendly ProgID (e.g., MyDVCDLL.INewDVCInterface).
  • A ProxyStubClsid32 value pointing to the CLSID of your proxy-stub DLL (more on this next).
• Register the Proxy-Stub DLL: When you compile your .idl with Midl, it generates proxy-stub source files (like _yourtlb_p.c). You need to compile these into a DLL (using Visual Studio’s compiler) and register it with regsvr32.exe your_proxy_stub.dll. This is critical for cross-apartment (STA/MTA) interface communication via Agile References—without it, COM can’t marshal your interface between processes.
• Verify DLL Threading Model: In your DLL’s CLSID registry entry (HKEY_CLASSES_ROOT\CLSID\{YOUR_DLL_CLSID}\InprocServer32), set the ThreadingModel value to Both or Free. Agile References require the DLL to support free-threading or dual-threading models to work correctly.

2. Address IWTSPlugin2 Compatibility #

Your hunch about upgrading to IWTSPlugin2 is spot-on:

• RDP’s mstsc.exe prioritizes querying IWTSPlugin2 first when loading DVC plugins. If your plugin only implements IWTSPlugin, it will fall back, but this can cause issues if your new interface relies on the extended plugin contract.
• Update your Delphi class to implement both IWTSPlugin (for backward compatibility) and IWTSPlugin2 (add the OnLogoff method required by the interface).
• Ensure your .idl correctly declares your plugin interface as inheriting from IWTSPlugin2 if you’re fully upgrading, and recompile the type library.
• Confirm your plugin’s CLSID is registered under the RDP plugin category: Add a subkey {7390F3D8-0439-4C05-91E3-C5CBFC15831A} under HKEY_CLASSES_ROOT\CLSID\{YOUR_DLL_CLSID}\Implemented Categories—this tells mstsc your DLL is a valid DVC plugin.

3. Debug Interface Query Failures #

To get to the root of the "interface not supported" error:

• Use OleView.exe: This Windows SDK tool lets you load your DLL directly to inspect its registered interfaces, type library, and proxy-stub associations. It’s invaluable for catching mismatched IIDs or missing registrations.
• Enable COM Logging: Create a LogToFile DWORD value set to 1 and a LogFilePath string value pointing to a log file (e.g., C:\COMlog.txt) under HKEY_LOCAL_MACHINE\Software\Microsoft\Ole\AppCompat. Run mstsc to load your plugin, then check the log for detailed errors about interface marshaling or query failures.
• Add Debug Logging to QueryInterface: Modify your Delphi plugin’s QueryInterface method to log which IIDs are being requested, ensuring your new interface is properly handled:

  function TMyDVPlugin.QueryInterface(const IID: TGUID; out Obj): HResult;
  begin
    if IsEqualGUID(IID, IID_INewDVCInterface) then
    begin
      OutputDebugString('New DVC interface requested');
      Obj := Self as INewDVCInterface;
      Result := S_OK;
      Exit;
    end;
    Result := inherited QueryInterface(IID, Obj);
  end;
  

  Use DebugView to monitor these debug messages and confirm your interface is being queried.

4. Replace tregsvr with a Custom Registration Tool #

Since tregsvr gives no useful error details, build a simple Delphi registration program to get clear feedback:

program RegMyDVCDLL;

uses
  ComServ, ComObj, Windows, SysUtils;

begin
  try
    if ParamCount <> 1 then
    begin
      Writeln('Usage: RegMyDVCDLL /REGSERVER or /UNREGSERVER');
      Exit;
    end;

    if UpperCase(ParamStr(1)) = '/REGSERVER' then
    begin
      RegisterServer;
      Writeln('DLL registered successfully.');
    end
    else if UpperCase(ParamStr(1)) = '/UNREGSERVER' then
    begin
      UnregisterServer;
      Writeln('DLL unregistered successfully.');
    end
    else
      Writeln('Invalid parameter.');
  except
    on E: Exception do
      Writeln('Registration failed: ', E.Message);
  end;
end.

Compile this, run it as administrator, and it will show you exact errors (like missing dependencies or invalid registry writes) that tregsvr hides.

内容的提问来源于stack exchange，提问作者David Bolton