Question

public static IList<string> GetAttribute_1(ModelContainer context, long productcatid)
{
    var query = from product in context.Products
                where product.ProductCategory_Id == productcatid
                select product.Attribute_1;

    return query.ToList();
}

how do i group by product.Attribute_1?

Answer 1

Grouping can be done by using the group by linq operator.

The syntax would be something like:

var query = from product in context.Products
                        where product.ProductCategory_Id == productcatid
                        group product by prodyct.Attribute_1 into g
                        select new { Attribute_1 = g.Key, Products = g }; 

Here you can find Linq samples for grouping.

But I suppose you want all the unqiue Attribute_1 properties returned from your function?

You could then use the Distinct operator. That will fiter your list of Attribute_1 strings to contain only unique values.