计算字符串中每种字母出现的次数

 　　        string msg = "WebApplication2";
                msg = msg.ToLower();
                Dictionary<char, int> dict = new Dictionary<char, int>();
                for (int i = 0; i < msg.Length; i++)
                {
                    if (char.IsLetter(msg[i]))
                    {
                        if (dict.ContainsKey(msg[i]))
                        {
                            dict[msg[i]]++;
                        }
                        else
                        {
                            dict[msg[i]] = 1;
                        }
                    }
                }

                foreach (var item in dict)
                {
                    Console.WriteLine("字母：{0}出现了：{1}次", item.Key, item.Value);
                    Console.ReadLine();
                }