How to write a LINQ query resulting in a Dictionary?

Question

 public class Person {     public string NickName{ get; set; }     public string Name{ get; set; } }  var pl = new List<Person>;  var q = from p in pl         where p.Name.First() == 'A'         orderby p.NickName         select new KeyValuePair<String, String>(p.NickName, p.Name);  var d1 = q.ToList(); // Gives List<KeyValuePair<string, string>> var d2 = q.ToDictionary(); // Does not compile 

How to get Dictionary<string, string>?

Answer 1

You need to specify the values for the Dictionary

var d2 = q.ToDictionary(p => p.NickName, p => p.Name); 

Answer 2

A dictionary cannot contain multiple equal keys, so you should ensure (or know) that this is not the case. You could use GroupBy to ensure it:

Dictionary<string, string> dict = pl         .Where(p => p.Name.First() == 'A')         .GroupBy(p => p.NickName)         .ToDictionary(g => g.Key, g => g.First().Name);