現在、Windows 7 Professional 64bit上にて、デスクトップ検索のアドオンをC#で開発しています。MSDNの技術情報や、ＳＤＫのサンプル、オープンソースプロジェクト「MILPA」に含まれているSearchHelperのコードをもとにDLLファイルを作ってはみたのですが、何かが不足しているようで、OSがアドオンとして認識しません（認識された場合はLoadメソッドが呼び出される）。ビルドのやりかたに問題があるかもしれませんので、SkyDriveにて問題のプロジェクトと、参考のための正常にアドオンとして動作するC言語バージョンのプロジェクトをアップロードしておりますので、よろしければ知恵をお貸しください。ちなみに、C++/CLIでアドオンを開発した場合、アドオンとしては認識するものの、CLIのクラスが参照された時点でなぜかフリーズしてしまいます。

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using CT = System.Runtime.InteropServices.ComTypes;
using System.Windows.Forms;
using Microsoft.Win32;
using System.IO;

namespace Test.ShellExt
{
	[ComImport]
	[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
	[Guid("0000010C-0000-0000-C000-000000000046")]
	public interface IPersist
	{
		void GetClassID(ref Guid pClassID);
	}

	[ComImport]
	[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
	[Guid("00000109-0000-0000-C000-000000000046")]
	public interface IPersistStream : IPersist
	{
		[PreserveSig]
		int IsDirty();
		void Load([In] CT.IStream pStm);
		void Save([In] CT.IStream pStm, [In, MarshalAs(UnmanagedType.Bool)] bool fClearDirty);
		void GetSizeMax(out long pcbSize);
	}

	[StructLayout(LayoutKind.Sequential)]
	public struct FILTERREGION
	{
		public uint cwcExtent;
		public uint cwcStart;
		public uint idChunk;
	}

	[StructLayout(LayoutKind.Explicit)]
	public struct PROPSPEC_DATA
	{
		[FieldOffset(0)]
		public UInt32 propid;
		[FieldOffset(0)]
		public IntPtr lpwstr;
	}

	[StructLayout(LayoutKind.Sequential)]
	public struct PROPSPEC
	{
		public uint ulKind;
		public PROPSPEC_DATA data;
	}

	[StructLayout(LayoutKind.Sequential)]
	public struct FULLPROPSPEC
	{
		public Guid guidPropSet;
		public PROPSPEC psProperty;
	}

	public enum CHUNK_BREAKTYPE : uint
	{
		CHUNK_NO_BREAK = 0,
		CHUNK_EOW = 1,
		CHUNK_EOS = 2,
		CHUNK_EOP = 3,
		CHUNK_EOC = 4,
	}

	[Flags]
	public enum CHUNKSTATE
	{
		CHUNK_TEXT = 1,
		CHUNK_VALUE = 2,
		CHUNK_FILTER_OWNED_VALUE = 4,
	}

	[Flags]
	public enum IFILTER_INIT
	{
		NONE = 0,
		CANON_PARAGRAPHS = 1,
		HARD_LINE_BREAKS = 2,
		CANON_HYPHENS = 4,
		CANON_SPACES = 8,
		APPLY_INDEX_ATTRIBUTES = 16,
		APPLY_OTHER_ATTRIBUTES = 32,
		INDEXING_ONLY = 64,
		SEARCH_LINKS = 128,
		APPLY_CRAWL_ATTRIBUTES = 256,
		FILTER_OWNED_VALUE_OK = 512
	}

	[StructLayout(LayoutKind.Sequential)]
	public struct STAT_CHUNK
	{
		public FULLPROPSPEC attribute;
		public CHUNK_BREAKTYPE breakType;
		public uint cwcLenSource;
		public uint cwcStartSource;
		public CHUNKSTATE flags;
		public uint idChunk;
		public uint idChunkSource;
		public uint locale;
	}

	[ComImport]
	[Guid("89BCB740-6119-101A-BCB7-00DD010655AF")]
	[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
	public interface IFilter
	{
		void Init(
			[MarshalAs(UnmanagedType.U4)] IFILTER_INIT grfFlags,
			uint cAttributes,
			[MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 1)] FULLPROPSPEC[] aAttributes,
			ref uint pdwFlags
			);
		[PreserveSig]
		int GetChunk(out STAT_CHUNK pStat);
		[PreserveSig]
		int GetText(ref int pcwcBuffer, [Out(), MarshalAs(UnmanagedType.LPWStr)] StringBuilder buffer);
		[PreserveSig]
		int GetValue(ref IntPtr ppPropValue);
		void BindRegion([MarshalAs(UnmanagedType.Struct)]FILTERREGION origPos, ref Guid riid, ref UIntPtr ppunk);
	}

	[ComVisible(true)]
	[Guid("A607B2D0-24BE-4FE3-8794-2CDAC3D40EA7")]
	[ClassInterface(ClassInterfaceType.None)]
	[ProgId("VVFilter")]
	public class TestFilter : IFilter, IPersistStream
	{
		public const int E_NOTIMPL = (unchecked((int)0x80004001L));
		public const int FILTER_E_NO_VALUES = (unchecked((int)0x80041706));
		public const int FILTER_E_NO_TEXT = (unchecked((int)0x80041705));

		public static readonly Guid TESTFILTER_ID = new Guid("A607B2D0-24BE-4FE3-8794-2CDAC3D40EA7");

		public TestFilter()
		{
		}

		~TestFilter()
		{
		}

		[ComRegisterFunction]
		public static void RegisterFunction(Type t)
		{
			try {
				Console.WriteLine("Regist start");
				RegistryKey regHKCR, subkey, guidkey;

				string fid = TESTFILTER_ID.ToString("B");
				string hid = "{AE63F9EB-DFA3-4032-A435-923E7C903E05}";

				regHKCR = Registry.ClassesRoot;
				subkey = regHKCR.CreateSubKey("CLSID");
				guidkey = subkey.CreateSubKey(fid);
				guidkey.SetValue(string.Empty, "Test IFilter Class");

				subkey = regHKCR.CreateSubKey("CLSID");
				guidkey = subkey.CreateSubKey(hid);
				guidkey.SetValue(string.Empty, "Test IFilter Handler");
				subkey = guidkey.CreateSubKey("PersistentAddinsRegistered");
				subkey = guidkey.CreateSubKey("PersistentAddinsRegistered\\{89BCB740-6119-101A-BCB7-00DD010655AF}");
				subkey.SetValue(string.Empty, fid);

				regHKCR = Registry.ClassesRoot;
				subkey = regHKCR.CreateSubKey(".test");
				subkey = subkey.CreateSubKey("PersistentHandler");
				subkey.SetValue(string.Empty, hid);

				subkey = Registry.LocalMachine.CreateSubKey("SOFTWARE\\Microsoft\\RSSearch\\ContentIndexCommon\\Filters\\Extension\\.test");
				subkey.SetValue(string.Empty, fid);

				Console.WriteLine("Finish");
			} catch (Exception ex) {
#if DEBUG
				Console.WriteLine(ex.Message + System.Environment.NewLine + ex.StackTrace);
#endif
			}
		}

		[ComUnregisterFunction]
		public static void UnregisterFunction(Type t)
		{
			Console.WriteLine("Unregist Start");
			RegistryKey regHKCR, subkey;

			try {
				regHKCR = Registry.ClassesRoot;
				subkey = regHKCR.OpenSubKey(".test", true);
				subkey.DeleteSubKeyTree("PersistentHandler");

				subkey = regHKCR.OpenSubKey("CLSID", true);
				subkey.DeleteSubKeyTree(TESTFILTER_ID.ToString("B"));
			} catch (Exception ex) {
				Console.Write(ex.Message);
			}
			Console.WriteLine("Unregist Finish");
		}


		// IFilter メンバ

		public void BindRegion([MarshalAs(UnmanagedType.Struct)]FILTERREGION origPos, ref Guid riid, ref UIntPtr ppunk)
		{
		}

		public int GetChunk(out STAT_CHUNK pStat)
		{
			throw new NotImplementedException();
		}

		public int GetText(ref int pcwcBuffer, [Out(), MarshalAs(UnmanagedType.LPWStr)] StringBuilder buffer)
		{
			return FILTER_E_NO_TEXT;
		}

		[PreserveSig]
		public int GetValue(ref IntPtr ppPropValue)
		{
			return FILTER_E_NO_VALUES;
		}

		public void Init(
			[MarshalAs(UnmanagedType.U4)] IFILTER_INIT grfFlags,
			uint cAttributes,
			[MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 1)] FULLPROPSPEC[] aAttributes,
			ref uint pdwFlags
			)
		{
		}

		// IPersistStream メンバ
		public void GetSizeMax(out long pcbSize)
		{
			pcbSize = 0;
		}

		public int IsDirty()
		{
			return E_NOTIMPL;
		}

		public void Load(CT.IStream pstm)
		{
			CT.STATSTG s;
			pstm.Stat(out s, 0);
		}

		public void Save(CT.IStream pStm, bool fClearDirty) { }

		// IPersist メンバ

		public void GetClassID(ref Guid pClassID)
		{
			pClassID = TESTFILTER_ID;
		}
	}
}