EF Core 3 filtering data with Extension method

user_1912372 0
Viewed 271

I am trying to make extension method for querying ef core. I have this Extension:

 public static class FiltrExtension
  {
     public static IQueryable<Contract> Filtr(this IQueryable<Contract> query, OrderFilter filter) 
     {
      if (!string.IsNullOrWhiteSpace(filter.OrderType))
         query.Where(x => x.OrderType == filter.OrderType);
      return query;
     }
  }

and then I am trying to filtr data, but the extension method doing nothing:

var data = await _uow.DatabaseContext.Contract.Filtr(filter).ToListAsync();

Can anybody help please?

entity-framework c#
2 Answers

You should put the result of query.Where(x => x.OrderType == filter.OrderType); into query like this

public static class FiltrExtension
  {
     public static IQueryable<Contract> Filtr(this IQueryable<Contract> query, OrderFilter filter) 
     {
      if (!string.IsNullOrWhiteSpace(filter.OrderType))
        query = query.Where(x => x.OrderType == filter.OrderType);
      return query;
     }
  }
user_70866780

You have to return the results :

public static class FiltrExtension
  {
     public static IQueryable<Contract> Filtr(this IQueryable<Contract> query, OrderFilter filter) 
     {
      if (!string.IsNullOrWhiteSpace(filter.OrderType))
         var result = query.Where(x => x.OrderType == filter.OrderType);
      return result;
     }
  }

You can user regular expressions :

  public static IQueryable<Contract> And<Contract>(this IQueryable<Contract> source, Expression<Func<Contract, bool>> predicate)
    {   
      return source.Where(predicate);    
    }
user_56855510
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