protected override void GetTileSource(int level, int row, int col, Action<System.Windows.Media.ImageSource> onComplete)
{
 string f = string.Empty;
 if (_cacheTileFormat.ToLower().Contains("png"))
  f = ".png";
 else if (_cacheTileFormat.ToLower().Contains("jpeg") || _cacheTileFormat.ToLower().Contains("jpg"))
  f = ".jpg";
 else
  throw new Exception("切片格式不明:" + _cacheTileFormat);
 #region Exploded读取
 if (_storageFormat == StorageFormat.esriMapCacheStorageModeExploded)
 {
  string baseUrl = _path;// "/WP_LocalCacheReader;component/Assets/usa_exploded/"
  baseUrl += @"/_alllayers";
  string l = "L";
  l = level.ToString().PadLeft(2, ‘0‘);
  string r = "R";
  r = String.Format("{0:X}", row).PadLeft(8, ‘0‘); //{0:X} 表示十六进制
  string c = "C";
  c = String.Format("{0:X}", col).PadLeft(8, ‘0‘);
  string str = baseUrl
  + @"/L" + l
  + @"/R" + r
  + @"/C" + c + f;
  BitmapImage img = new BitmapImage(new Uri(str,UriKind.RelativeOrAbsolute))
  {
   CreateOptions = BitmapCreateOptions.DelayCreation
  };
  img.ImageFailed += (s, a) =>
  {
   string uri = _path + "/missing" + _tileRows.ToString() + f;
   BitmapImage image = new BitmapImage(new Uri(uri, UriKind.RelativeOrAbsolute))
   {
    CreateOptions = BitmapCreateOptions.DelayCreation
   };
   onComplete(image);
   return;
  };
  onComplete(img);
 }
 #endregion
}

ArcGIS Server的Tile的松散型存储（Exploded）