C#问题！紧急情况！

将给定字符串去掉重复的字符后，按照字符ASCII码顺序从小到大排序后输出。怎么样用C#解决

var r = str.Distinct().OrderBy(c => c);
            Console.WriteLine( string.Join("", r));

string[] vv = { "1", "2", "A", "a", "B", "b" };
Array.Sort(vv);