#region 高于 v4.4 版本 解析真实路径

        public static String GetPath(Context context,Android.Net.Uri uri)

        {

            bool isKitKat = Build.VERSION.SdkInt >= BuildVersionCodes.Kitkat;

            // DocumentProvider

            if (isKitKat && DocumentsContract.IsDocumentUri(context, uri))

            {

                // ExternalStorageProvider

                if (isExternalStorageDocument(uri))

                {

                    String docId = DocumentsContract.GetDocumentId(uri);

                    String[] split = docId.Split(':');

                    String type = split[];

                    if ("primary".Equals(type.ToLower()))

                    {

                        return Android.OS.Environment.ExternalStorageDirectory + "/" + split[];

                    }

                    // TODO handle non-primary volumes

                }

                // DownloadsProvider

                else if (isDownloadsDocument(uri))

                {

                    String id = DocumentsContract.GetDocumentId(uri);

                    Android.Net.Uri contentUri = ContentUris.WithAppendedId(

                            Android.Net.Uri.Parse("content://downloads/public_downloads"),long.Parse(id));

                    return getDataColumn(context, contentUri, null, null);

                }

                // MediaProvider

                else if (isMediaDocument(uri))

                {

                    String docId = DocumentsContract.GetDocumentId(uri);

                    String[] split = docId.Split(':');

                    String type = split[];

                    Android.Net.Uri contentUri = null;

                    if ("image".Equals(type))

                    {

                        contentUri = MediaStore.Images.Media.ExternalContentUri;

                    }

                    else if ("video".Equals(type))

                    {

                        contentUri = MediaStore.Video.Media.ExternalContentUri;

                    }

                    else if ("audio".Equals(type))

                    {

                        contentUri = MediaStore.Audio.Media.ExternalContentUri;

                    }

                    String selection = "_id=?";

                    String[] selectionArgs = new String[] {

                    split[]

            };

                    return getDataColumn(context, contentUri, selection, selectionArgs);

                }

            }

            // MediaStore (and general)

            else if ("content".Equals(uri.Scheme.ToLower()))

            {

                // Return the remote address

                if (isGooglePhotosUri(uri))

                    return uri.LastPathSegment;

                return getDataColumn(context, uri, null, null);

            }

            // File

            else if ("file".Equals(uri.Scheme.ToLower()))

            {

                return uri.Path;

            }

            return null;

        }

        /**

         * Get the value of the data column for this Uri. This is useful for

         * MediaStore Uris, and other file-based ContentProviders.

         *

         * @param context The context.

         * @param uri The Uri to query.

         * @param selection (Optional) Filter used in the query.

         * @param selectionArgs (Optional) Selection arguments used in the query.

         * @return The value of the _data column, which is typically a file path.

         */

        public static String getDataColumn(Context context,Android.Net.Uri uri, String selection,

                String[] selectionArgs)

        {

            ICursor cursor = null;

            String column = "_data";

            String[] projection = {

                column

            };

            try

            {

                cursor = context.ContentResolver.Query(uri, projection, selection, selectionArgs,

                        null);

                if (cursor != null && cursor.MoveToFirst())

                {

                    int index = cursor.GetColumnIndexOrThrow(column);

                    return cursor.GetString(index);

                }

            }

            finally

            {

                if (cursor != null)

                    cursor.Close();

            }

            return null;

        }

        /**

         * @param uri The Uri to check.

         * @return Whether the Uri authority is ExternalStorageProvider.

         */

        public static bool isExternalStorageDocument(Android.Net.Uri uri)

        {

            return "com.android.externalstorage.documents".Equals(uri.Authority);

        }

        /**

         * @param uri The Uri to check.

         * @return Whether the Uri authority is DownloadsProvider.

         */

        public static bool isDownloadsDocument(Android.Net.Uri uri)

        {

            return "com.android.providers.downloads.documents".Equals(uri.Authority);

        }

        /**

         * @param uri The Uri to check.

         * @return Whether the Uri authority is MediaProvider.

         */

        public static bool isMediaDocument(Android.Net.Uri uri)

        {

            return "com.android.providers.media.documents".Equals(uri.Authority);

        }

        /**

         * @param uri The Uri to check.

         * @return Whether the Uri authority is Google Photos.

         */

        public static bool isGooglePhotosUri(Android.Net.Uri uri)

        {

            return "com.google.android.apps.photos.content".Equals(uri.Authority);

        }

        #endregion