public async Task <IActionResult> PutExamCenter([FromRoute] int id, [FromBody] ExamCenter center)
 {
     if (!ModelState.IsValid)
     {
         return(BadRequest(ModelState));
     }
     if (id != center.CenterId)
     {
         return(BadRequest());
     }
     try
     {
         _repo.Update(center);
         var save = await _repo.SaveAsync(center);
     }
     catch (DbUpdateConcurrencyException)
     {
         if (!CenterExists(id))
         {
             return(NotFound());
         }
         else
         {
             throw;
         }
     }
     return(NoContent());
 }
        public async Task <ActionResult> PostCenter([FromBody] ExamCenter center)
        {
            if (!ModelState.IsValid)
            {
                return(BadRequest(ModelState));
            }
            _repo.Add(center);
            var save = await _repo.SaveAsync(center);

            return(CreatedAtAction("GetCenter", new { id = center.CenterId }, center));
        }