c# list distinct by property code example

Example 1: c# distinct by property

objList.Select(o=>o.typeId).Distinct()

Example 2: c# distinct comparer multiple properties

List distinctPeople = allPeople
  .GroupBy(p => new {p.PersonId, p.FavoriteColor} )
  .Select(g => g.First())
  .ToList();

Example 3: c# distinct array of objects by values

var uniquePersons = persons.GroupBy(p => p.Email)
                           .Select(grp => grp.First())
                           .ToArray();

Example 4: c# distinct comparer multiple properties

public static IEnumerable DistinctBy
    (this IEnumerable source, Func keySelector)
{
    HashSet seenKeys = new HashSet();
    foreach (TSource element in source)
    {
        if (seenKeys.Add(keySelector(element)))
        {
            yield return element;
        }
    }
}

Example 5: c# get distinct values all fields from list

if (!IsPostBack) {  
       GridView1.DataSource = GetProducts()
                              .GroupBy(o => new { o.Make, o.Model })
                              .Select(o => o.FirstOrDefault());
       GridView1.DataBind();
}