CODEWITHSUNDEEP
c#wpfdb2
Ben
Ben

Reputation: 1153

Get Distinct property values from List

I am trying to get distinct FullNames from a list that contains FullNames and IDs then displaying these in a listBox control. Is there a simple way to do it? Thanks Ben

using (DB2DataReader dr = command.ExecuteReader())
            {
                while (dr.Read())
                {

                Contact contact = new Contact();

                contact.ContactID = Convert.ToInt32(dr["CONTACT_ID"]);
                contact.FullName= dr["FULL_NAME"].ToString();


                myContacts.Add(contact);

                //contactsListBox.ItemsSource = myContacts.Distinct FullName??


            }
        }

Upvotes: 14

Views: 16687

Answers (3)

Chauhan
Chauhan

Reputation: 1

we can achieve like this:

var distinctItems = myItemsList.ToList().DistinctBy(x => x.ItemName);

Upvotes: 0

Vokinneberg
Vokinneberg

Reputation: 2017

I think you can use different approaches here:

  1. Make Sql query that queries distinct values.

  2. Check that contact already in list. This approach assume that your class must redefine euqality operator. Or you can check that this contact id is already in list.

  3. Use Linq query as mentioned above.

Upvotes: 0

Marc Gravell
Marc Gravell

Reputation: 1062895

With LINQ:

var uniqueNames = myContacts.Select(c => c.FullName).Distinct().ToList();

should work. If the order is unimportant you could also use:

var names = new HashSet<string>();
while(dr.Read()) {
    ...
    names.Add(contact.FullName);
}

(and then use ToList() / OrderBy whatever you need)

Upvotes: 23

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