/Wrapper/AutoHotkeyInit.cs

/*
 * All code in 'static AutoHotkey()' is taken from here:
 * http://stackoverflow.com/questions/666799/embedding-unmanaged-dll-into-a-managed-c-dll/768429#768429
 * All credit goes to the author
 */

using System;
using System.Reflection;
using System.IO;

namespace AhkWrapper
{
    public partial class AutoHotkey
    {
        static AutoHotkey()
        {
            if (File.Exists("AutoHotkey.dll"))
            {
                IntPtr h = Win32.LoadLibrary("AutoHotkey.dll");
                return;
            }

            // Get a temporary directory in which we can store the unmanaged DLL, with
            // this assembly's version number in the path in order to avoid version
            // conflicts in case two applications are running at once with different versions
            string dirName = Path.Combine(Path.GetTempPath(), "AhkWrapper." +
              Assembly.GetExecutingAssembly().GetName().Version.ToString());
            if (!Directory.Exists(dirName))
                Directory.CreateDirectory(dirName);
            string dllPath = Path.Combine(dirName, "AutoHotkey.dll");

            // Get the embedded resource stream that holds the Internal DLL in this assembly.
            // The name looks funny because it must be the default namespace of this project
            // (MyAssembly.) plus the name of the Properties subdirectory where the
            // embedded resource resides (Properties.) plus the name of the file.
            using (Stream stm = Assembly.GetExecutingAssembly().GetManifestResourceStream(
              "AhkWrapper.embed.AutoHotkey.dll"))
            {
                // Copy the assembly to the temporary file
                try
                {
                    using (Stream outFile = File.Create(dllPath))
                    {
                        const int sz = 4096;
                        byte[] buf = new byte[sz];
                        while (true)
                        {
                            int nRead = stm.Read(buf, 0, sz);
                            if (nRead < 1)
                                break;
                            outFile.Write(buf, 0, nRead);
                        }
                    }
                }
                catch
                {
                    // This may happen if another process has already created and loaded the file.
                    // Since the directory includes the version number of this assembly we can
                    // assume that it's the same bits, so we just ignore the excecption here and
                    // load the DLL.
                }
            }

            // We must explicitly load the DLL here because the temporary directory 
            // is not in the PATH.
            // Once it is loaded, the DllImport directives that use the DLL will use
            // the one that is already loaded into the process.
            IntPtr h = Win32.LoadLibrary(dllPath);
        }

    }
}