Filtering data on basis of attribute values

Question

I am writing code to filter data on basis of attribute values. It is possible that the user can select multiple values.

How can this be better?

Models.Products filter(ViewModel.Filter search,IEnumerable<Models.Products> product)
{
 if (search.filter!= null && search.filter.Count>0)
 {
 var f = search.First();
 var tempProducts = products
 .Where(c => c.productattributes
 .Where(a => a.AttributeId == f.Id && f.Value.Contains(a.Value))
 .Any());
 search.filter.Remove(f);
 foreach (var fs in search)
 {
 var p = products.Where(c => c.productattributes.Where(a => a.AttributeId == fs.Id && fs.Value.Contains(a.Value)).Any());
 tempProducts = tempProducts.Union(p);
 }
 products = tempProducts;
 }
}

Filter View Model:

public class Filters
{
 public long Id { get; set; }
 public IEnumerable<string> Value { get; set; }
}

• t3chb0t: Where's the return? I thought the function in the method declaration was a typo but there's more. Is this even working?

Answer 1

Your code appears to be incomplete but I've provided some ideas below.

Filters Class

I'm looking at your Filters class:

public class Filters
{
 public long Id { get; set; }
 public IEnumerable<string> Value { get; set; }
}

From this, I am assuming that the purpose of this is to hold the Attribute Id (key) and Search Keywords (value). So, I would propose you just use a Dictionary<long, List<string>> -- note that I changed the type of your Search Keywords to a List as I am not seeing any reason within your code example as to why it should/would need to be an IEnumberable type.

That would then change the method:

• Method renamed
• Parameter updated to use Dictionary instead (per above)

Here is the updated method

public IEnumerable<Product> FilterProductsByAttributeId(
 Dictionary<long, List<string>> filters,
 IEnumerable<Product> products)
{
 // your method contents here
}

---

Filter Method

I'm not sure why you have a complicated initializer for your tempProducts, but maybe it can be improved to something like this?

public IEnumerable<Product> FilterProductsByAttributeId(Dictionary<long, List<string>> filters, IEnumerable<Product> products)
{
 if (products == null) throw new ArgumentNullException(nameof(products));
 if (filters == null) throw new ArgumentNullException(nameof(filters));
 IEnumerable<Product> result = new List<Product>();
 foreach (var f in filters)
 {
 result = result.Union(products.Where(p => p.ProductAttributes
 .Where(a => a.AttributeId == f.Key && f.Value.Contains(a.Value)).Any()));
 }
 return result; 
}

Alternatively you can use the Aggregate extension:

return 
 filters
 .Aggregate(
 new List<Product>(), 
 (current, next) => current.Union(..)
 );

• t3chb0t: I hope you don't mind the edit ;-)
• Svek: Not a problem. I appreciate the help! It seems you had a typo also! Haha