Char Duplicate Removal from List

[kiail]

I have a program, and I'm trying to remove duplicate characters. I have tried using toLower(), but it doesn't work...I'm not sure where to go from here. Any help in the right direction would be great!

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace SortingLetters

{

static class RandomLetter
{
    static Random _random = new Random();
    public static char GetLetter()
    {
        // This method returns a random lowercase letter.
        int num = _random.Next(0, 26); // Zero to 25
        char let = (char)('a' + num);
        return let;
    }
}

class SortingLetters
{
    static void Main()
    {
        int max = 30;

        List<char> items = new List<char>();
        int counter = 0;
        // Get random lowercase letters.
        while (counter < max)
        {
            counter++;
            items.Add(RandomLetter.GetLetter());
        }

        // ascending order
        var itemSorted =
           from it in items
           orderby it ascending
           select it;

        // writes ascending order to console
        foreach (var element in itemSorted)
            Console.Write("{0}", element);
        Console.Write("\n");

        // descending order
        var itemDescend =
           from it in items
           orderby it descending
           select it;


        // writes ascending order to console
        foreach (var element in itemDescend)
            Console.Write("{0}", element);
        Console.Write("\n");
    }
}

}

`

[Momerath]

Use Distinct:

var itemSorted =
    (from it in items
     orderby it ascending
     select it).Distinct();

[kiail]

That's awesome, thank you Momerath.