Remove duplicates from EntityCollection

Question

I have an EntityCollection which contains members coming from different Marketing Lists. Because a person can exist in various MarketingLists my EntityCollection can contain the same person multiple times.

To have this data initially grouped I do the following:

var groupedCustomerList = listMembers.Entities.GroupBy(u => u.Id).Select(grp => grp.ToList());

My EntityCollection contains also an Attribute called "priority" which leads to the following if the same person is found multiple times

Group_1
- Person_1 (priority 1)

Group_2
- Person_1 (priority 2)
- Person_2 (priority 1)

What I need to achieve is to remove the duplicate person(s) with the lower priority -> Person_1 in Group_2 needs to be removed.

What I have tried so far is:

foreach (var item in groupedCustomerList)
{
    if (item.Count > 1)
    {
        // order the items in the group by priority set in the SelectionRow and take the first 
        // entry with the highest priority
        var element = item.OrderBy(o => o.Attributes[AttributeNames.SelectionRow.SelectionRowPriority]).Take(1).ToList();
        listMembersConsolidated.Add(element[0]);

    }
    else
    {
        listMembersConsolidated.Add(item[0]);
    }
}

But this does not give me the desired result -> always the same person in the result

Does anybody have a hint for me?

Would be highly appreciated.

Thank you in advance.

Answer 1

I just created very simple console application in c# based on entity framework.

I created Product Entity and added around 15 products. Then I added all these entity products in an Entity collection. So that now I have almost same req as you need. What I did is that keep only those Records in my entitycollection which have UnitsInStock highest among a Product ID.

For ex: For Product ID 1 I have only taken record with UnitsInStock =40

using System;
using System.Collections.Generic;
using System.Data.Entity.Core.Objects.DataClasses;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EntityCollectionTesting
{
    class Program
    {
        static void Main(string[] args)
        {
            var productList =
                    new List<Product> {
                    new Product { ProductID = 1, ProductName = "Chai", Category = "Beverages", UnitPrice = 18.0000M, UnitsInStock = 39 },
                    new Product { ProductID = 2, ProductName = "Chang", Category = "Beverages", UnitPrice = 19.0000M, UnitsInStock = 17 },
                    new Product { ProductID = 3, ProductName = "Aniseed Syrup", Category = "Condiments", UnitPrice = 10.0000M, UnitsInStock = 13 },
                    new Product { ProductID = 4, ProductName = "Chef Anton's Cajun Seasoning", Category = "Condiments", UnitPrice = 22.0000M, UnitsInStock = 53 },
                    new Product { ProductID = 5, ProductName = "Chef Anton's Gumbo Mix", Category = "Condiments", UnitPrice = 21.3500M, UnitsInStock = 0 },
                    new Product { ProductID = 6, ProductName = "Grandma's Boysenberry Spread", Category = "Condiments", UnitPrice = 25.0000M, UnitsInStock = 120 },
                    new Product { ProductID = 7, ProductName = "Uncle Bob's Organic Dried Pears", Category = "Produce", UnitPrice = 30.0000M, UnitsInStock = 15 },
                    new Product { ProductID = 8, ProductName = "Northwoods Cranberry Sauce", Category = "Condiments", UnitPrice = 40.0000M, UnitsInStock = 6 },
                    new Product { ProductID = 9, ProductName = "Mishi Kobe Niku", Category = "Meat/Poultry", UnitPrice = 97.0000M, UnitsInStock = 29 },
                    new Product { ProductID = 10, ProductName = "Ikura", Category = "Seafood", UnitPrice = 31.0000M, UnitsInStock = 31 },
                    new Product { ProductID = 1, ProductName = "Ikura", Category = "Seafood", UnitPrice = 31.0000M, UnitsInStock = 40 },
                    new Product { ProductID = 2, ProductName = "Ikura", Category = "Seafood", UnitPrice = 31.0000M, UnitsInStock = 56 },
                    new Product { ProductID = 3, ProductName = "Ikura", Category = "Seafood", UnitPrice = 31.0000M, UnitsInStock = 11 },
                    new Product { ProductID = 4, ProductName = "Ikura", Category = "Seafood", UnitPrice = 31.0000M, UnitsInStock = 12 },
                    new Product { ProductID = 5, ProductName = "Ikura", Category = "Seafood", UnitPrice = 31.0000M, UnitsInStock = 1 }                       

                };

            EntityCollection<Product> entityCollection = new EntityCollection<Product>();
            EntityCollection<Product> newCollection = new EntityCollection<Product>();

            foreach (var VARIABLE in productList)
            {
                entityCollection.Add(VARIABLE);
                newCollection.Add(VARIABLE);
            }

            foreach (var ec in entityCollection)
            {
                foreach (var nc in newCollection)
                {
                    if (ec.ProductID == nc.ProductID)
                    {
                        if (ec.UnitsInStock > nc.UnitsInStock)
                        {
                            newCollection.Remove(nc);

                            break;
                        }
                    }
                }
            }
            foreach (var VARIABLE in newCollection)
            {
                Console.WriteLine($"{VARIABLE.ProductID} and {VARIABLE.UnitsInStock}");
            }

            Console.ReadLine();
        }
    }
    public class Product
    {
        public int ProductID { get; set; }
        public string ProductName { get; set; }
        public string Category { get; set; }
        public decimal UnitPrice { get; set; }
        public int UnitsInStock { get; set; }
    }
}

Answer 2

You can try this. I've used sample list but you can apply with your entity collection. Enjoy coding

List<Employee> employees = new List<Employee>();
var newEmployeList = employees.Distinct().ToList();