public async Task DeleteAsync(TEntity entity)
{
if (entity == null)
{
throw new ArgumentNullException("entity");
}
var isDetached = !_db.Set <TEntity>().Local.Any(a => a.Id == entity.Id);
if (isDetached)
{
_db.Entry(entity).State = EntityState.Modified;
}
_db.Set <TEntity>().Remove(entity);
await _db.SaveChangesAsync();
}
