CSHARP

return last row if all other condition fails in linq c#

Mains.GroupBy(l => l.ContactID)
.Select(g=>g.OrderByDescending(c=>c.ID).FirstOrDefault()) 
.ToList()

return last row if all other condition fails in linq c#

var grouped = Mains.GroupBy(l => l.ContactID);
var ids = grouped.Select(g => g.Max(x => x.Id));
var result = grouped.Where(g => ids.Contains(g.Id));