public MapSampleDataDao()
 {
     _context = MapSampleDataContext.Instance;
 }
 public MapSampleDataDao(MapSampleDataContext context)
 {
     _context = context;
 }
 public MapSampleDataDao(MapSampleDataContext context)
 {
     _context = context;
 }
 public MapSampleDataDao()
 {
     _context = MapSampleDataContext.Instance;
 }