怎么根据每个单词的首字母进行排序

SortedList mySortedList = new SortedList();        //while if for break switch        mySortedList["while"] = "while";        mySortedList["if"] = "if";        mySortedList["for"] = "for";        mySortedList["break"] = "break";        mySortedList["switch"] = "switch";        if (!IsPostBack)        {            string s=string.Empty;            foreach (DictionaryEntry Item in mySortedList)            {                s += Item.Value.ToString()+" ";            }            Response.Write(s);        }