easyhookでexttextoutwをフックしたい

EasyHook-Tutorialsのサンプルを変更して、exttextoutwをフックするようにプログラムを書きました。しかし、notepad.exeで実行してもhookのメッセージが表示されません。

なにが悪いのでしょうか？

変更したコードは下記のとおりです。
FileMonitorHook以外は変更しておりません。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace FileMonitorHook
{
    public class InjectionEntryPoint: EasyHook.IEntryPoint
    {
        ServerInterface _server = null;
        Queue<string> _messageQueue = new Queue<string>();

        [StructLayout(LayoutKind.Sequential)]
        public struct RECT
        {
            public long left;
            public long top;
            public long right;
            public long bottom;
        }

        public InjectionEntryPoint(
            EasyHook.RemoteHooking.IContext context,
            string channelName)
        {
            _server = EasyHook.RemoteHooking.IpcConnectClient<ServerInterface>(channelName);
            _server.Ping();
        }

        public void Run(
            EasyHook.RemoteHooking.IContext context,
            string channelName)
        {
            _server.IsInstalled(EasyHook.RemoteHooking.GetCurrentProcessId());

            var ExtTextOutHook = EasyHook.LocalHook.Create(
                EasyHook.LocalHook.GetProcAddress("Gdi32.dll", "ExtTextOutW"),
                new ExtTextOut_Delegate(ExtTextOut_Hook),
                this);

            _server.ReportMessage("ExtTextOut hook installed");

            EasyHook.RemoteHooking.WakeUpProcess();

            try
            {
                // Loop until FileMonitor closes (i.e. IPC fails)
                while (true)
                {
                    System.Threading.Thread.Sleep(500);
                    string[] queued = null;
                    lock (_messageQueue)
                    {
                        queued = _messageQueue.ToArray();
                        _messageQueue.Clear();
                    }
                    if (queued != null && queued.Length > 0)
                    {
                        _server.ReportMessages(queued);
                    }
                    else
                    {
                        _server.Ping();
                    }
                }
            }
            catch
            {
            }

            ExtTextOutHook.Dispose();
            EasyHook.LocalHook.Release();
        }

        #region ExtTextOutW Hook

        [UnmanagedFunctionPointer(CallingConvention.StdCall,
                    CharSet = CharSet.Unicode,
                    SetLastError = true)]
        delegate bool ExtTextOut_Delegate(
            IntPtr hdc,
            int x,
            int y,
            uint fuOptions,
            [In] ref RECT lprc,
            string lpString,
            uint cbCount,
            [In] IntPtr lpDx);

        [DllImport("Gdi32.dll",
            CharSet = CharSet.Unicode,
            SetLastError = true, CallingConvention = CallingConvention.StdCall)]
        static extern bool ExtTextOutW(
            IntPtr hdc,
            int x,
            int y,
            uint fuOptions,
            [In] ref RECT lprc,
            string lpString,
            uint cbCount,
            [In] IntPtr lpDx);

        bool ExtTextOut_Hook(
            IntPtr hdc,
            int x,
            int y,
            uint fuOptions,
            [In] ref RECT lprc,
            string lpString,
            uint cbCount,
            [In] IntPtr lpDx)
        {
            try
            {
                lock (this._messageQueue)
                {
                    this._messageQueue.Enqueue("ExtTextOut_Hook called");
                }
            }
            catch
            {
            }

            return ExtTextOutW(
                hdc,
                x,
                y,
                fuOptions,
                ref lprc,
                lpString,
                cbCount,
                lpDx);
        }

        #endregion
    }
}