我已经解决了完全相同的问题-为.NET包装libspotify。我走了IntPtr路线，并编写了一个助手类来进行编组。我发现阵列编组简直让人抓狂，不值得把你的头发扯掉。

这是助手类：

https://github.com/openhome/ohLibSpotify/blob/master/src/ohLibSpotify/Utf8String.cs#L99

简化版：

internal class Utf8String : IDisposable
{
    IntPtr iPtr;
    public IntPtr IntPtr { get { return iPtr; } }
    public int BufferLength { get { return iBufferSize; } }
    int iBufferSize;
    public Utf8String(string aValue)
    {
        if (aValue == null)
        {
            iPtr = IntPtr.Zero;
        }
        else
        {
            byte[] bytes = Encoding.UTF8.GetBytes(aValue);
            iPtr = Marshal.AllocHGlobal(bytes.Length + 1);
            Marshal.Copy(bytes, 0, iPtr, bytes.Length);
            Marshal.WriteByte(iPtr, bytes.Length, 0);
            iBufferSize = bytes.Length + 1;
        }
    }
    public void Dispose()
    {
        if (iPtr != IntPtr.Zero)
        {
            Marshal.FreeHGlobal(iPtr);
            iPtr = IntPtr.Zero;
        }
    }
}

用法如下：

https://github.com/openhome/ohLibSpotify/blob/master/src/ohLibSpotify/SpotifySession.cs#L104

public static SpotifySession Create(SpotifySessionConfig config)
{
    IntPtr sessionPtr = IntPtr.Zero;
    IntPtr listenerToken;
    using (var cacheLocation = SpotifyMarshalling.StringToUtf8(config.CacheLocation))
    using (var settingsLocation = SpotifyMarshalling.StringToUtf8(config.SettingsLocation))
    using (var userAgent = SpotifyMarshalling.StringToUtf8(config.UserAgent))
    using (var deviceId = SpotifyMarshalling.StringToUtf8(config.DeviceId))
    using (var proxy = SpotifyMarshalling.StringToUtf8(config.Proxy))
    using (var proxyUsername = SpotifyMarshalling.StringToUtf8(config.ProxyUsername))
    using (var proxyPassword = SpotifyMarshalling.StringToUtf8(config.ProxyPassword))
    using (var traceFile = SpotifyMarshalling.StringToUtf8(config.TraceFile))
    {
        IntPtr appKeyPtr = IntPtr.Zero;
        listenerToken = ListenerTable.PutUniqueObject(config.Listener, config.UserData);
        try
        {
            NativeCallbackAllocation.AddRef();
            byte[] appkey = config.ApplicationKey;
            appKeyPtr = Marshal.AllocHGlobal(appkey.Length);
            Marshal.Copy(config.ApplicationKey, 0, appKeyPtr, appkey.Length);
            sp_session_config nativeConfig = new sp_session_config {
                api_version = config.ApiVersion,
                cache_location = cacheLocation.IntPtr,
                settings_location = settingsLocation.IntPtr,
                application_key = appKeyPtr,
                application_key_size = (UIntPtr)appkey.Length,
                user_agent = userAgent.IntPtr,
                callbacks = SessionDelegates.CallbacksPtr,
                userdata = listenerToken,
                compress_playlists = config.CompressPlaylists,
                dont_save_metadata_for_playlists = config.DontSaveMetadataForPlaylists,
                initially_unload_playlists = config.InitiallyUnloadPlaylists,
                device_id = deviceId.IntPtr,
                proxy = proxy.IntPtr,
                proxy_username = proxyUsername.IntPtr,
                proxy_password = proxyPassword.IntPtr,
                tracefile = traceFile.IntPtr,
            };
            // Note: sp_session_create will invoke a callback, so it's important that
            // we have already done ListenerTable.PutUniqueObject before this point.
            var error = NativeMethods.sp_session_create(ref nativeConfig, ref sessionPtr);
            SpotifyMarshalling.CheckError(error);
        }
        catch
        {
            ListenerTable.ReleaseObject(listenerToken);
            NativeCallbackAllocation.ReleaseRef();
            throw;
        }
        finally
        {
            if (appKeyPtr != IntPtr.Zero)
            {
                Marshal.FreeHGlobal(appKeyPtr);
            }
        }
    }
    SpotifySession session = SessionTable.GetUniqueObject(sessionPtr);
    session.Listener = config.Listener;
    session.UserData = config.UserData;
    session.ListenerToken = listenerToken;
    return session;
}

因为手工编写这些东西很快就会变得乏味，所以绝大多数包装器和DllImport声明都是从api.h头文件自动生成的。（因此，你不会在github repo中找到它们，你需要下载项目并构建它来查看所有生成的代码。）

这一切都是自由许可的（2段BSD），所以可以随意使用它或借用它的一些部分。