public async Task UpdateAsync(T item)
 {
     using (var _context = new MarketAnalyzerDBContext())
     {
         _context.Entry(item).State = EntityState.Modified;
         await _context.SaveChangesAsync();
     }
 }
 public void Update(T item)
 {
     using (var _context = new MarketAnalyzerDBContext())
     {
         _context.Entry(item).State = EntityState.Modified;
         _context.SaveChanges();
     }
 }
 public async Task UpdateListAsync(List <T> items)
 {
     using (var _context = new MarketAnalyzerDBContext())
     {
         foreach (var item in items)
         {
             _context.Entry(item).State = EntityState.Modified;
         }
         await _context.SaveChangesAsync();
     }
 }