如何在Xamarin中获取视频缩略图？

Question

以下代码从手机/ SD卡上的本地图片中获取图像缩略图：

    public Task<List<Album>> GetAllAlbumsAndPhotos(object activity)
    {
        Activity activ = activity as Activity;
        List<Album> albums = new List<Album>();

        // which image properties are we querying
        String[] projection = new String[] 
        {   
            MediaStore.Images.Media.InterfaceConsts.BucketId,
            MediaStore.Images.Media.InterfaceConsts.BucketDisplayName,
            MediaStore.Images.Media.InterfaceConsts.DateTaken,
            MediaStore.Images.Media.InterfaceConsts.DateAdded,
            MediaStore.Images.Media.InterfaceConsts.Data
        };

        // Get the base URI for the People table in the Contacts content provider.
        AndroidNet.Uri images = MediaStore.Images.Media.ExternalContentUri;

        // Make the query.
        var cursor = activ.ContentResolver.Query(images,
                                                projection, // Which columns to return
                                                "",         // Which rows to return (all rows)
                                                null,       // Selection arguments (none)
                                                ""          // Ordering
                                                );

        if (cursor.MoveToFirst())
        {
            int bucketColumn = cursor.GetColumnIndex(MediaStore.Images.Media.InterfaceConsts.BucketDisplayName);
            int takenColumn = cursor.GetColumnIndex(MediaStore.Images.Media.InterfaceConsts.DateTaken);
            int addedColumn = cursor.GetColumnIndex(MediaStore.Images.Media.InterfaceConsts.DateAdded);
            int dataColumn = cursor.GetColumnIndex(MediaStore.Images.Media.InterfaceConsts.Data);

            do
            {
                .
                .
                .

            } while (cursor.MoveToNext());
        }

        return Task.FromResult(albums);
    }

如何添加视频缩略图？可以使用相同的代码完成，还是必须独立于此代码块完成？