Contains() method not working in Linq to Entities

Question

_{Tuesday, March 8, 2011 6:29 AM}

I am building a web application in asp.Net 4.0 and entity framework.

I am trying to retrieve a list of products based on a collection of id's.

I first gather all the id's in a collection and then pass it to the linq query. I am trying to get a functionality similar to the IN clause in SQL.

The problem seems to be with the Contains() method in the Linq to entities query.

Here is my Linq code:

public IList<Product> fn_getProductsBySubCategoryIdandBrandIDs(ArrayList alSelectedIDs)
    {
        IList<Product> objCProduct = null;
        try
        {
            objDataContext = compareIndiaDataContext;
            //objCProduct = objDataContext.Products.Where(db => ( (db.Product_SubCatID = iSubCategoryID) && (alSelectedIDs.Contains(db.Product_BrandID))).ToList<Product>();
            objCProduct = objDataContext.Products.Where(db => alSelectedIDs.Contains(db.Product_BrandID)).ToList<Product>();
            

            return objCProduct;


        }
        catch (Exception ex)
        {
            return objCProduct;
        }
}

I got the above Linq to entities method from here: http://msdn.microsoft.com/en-us/library/bb896342.aspx

 

 

 

All replies (2)

_{Friday, April 1, 2011 4:04 AM ✅Answered}

 

Use AsEnumerable after the 'tableName' and before applying the 'where' method.

objDataContext = compareIndiaDataContext;
            objCProduct = objDataContext.Products**.AsEnumerable()**.Where(db => alSelectedIDs.Contains(db.Product_BrandID)).ToList<Product>();
            return objCProduct;

---

_{Wednesday, March 9, 2011 9:16 PM}

Yes, Contains can only match one condition. I suggest you trying the way：

Using List<T> and IndexOfAny method. Here's my sample:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Data;
using System.Text.RegularExpressions;
using System.Xml.Linq;

namespace ConsoleApplication2
{
   
    class Program
    {
        static void Main(string[] args)
        {
            string[] words = new string[] { "Apple","Banana","Pineapple","Age"};

            //Put what you want to find into a List class
            List<char> chars = new List<char>()
            {
                'a',
                'b'
            };

            //Finding all words that start with a or b
            var result = from w in words.AsEnumerable()
                         where w.ToLower().IndexOfAny(chars.ToArray()) == 0
                         select w;

            foreach (var item in result)
            {
                Console.WriteLine(item);
            }
        }

    }

}