根據大洲編號從緩存獲取按字母分類的城市列表

在大部分的時候要在頁面上顯示字母和 國家頁面 ，可以採用類中有類的方法，綁定reapter控件就可以  

public static List<Letter_City> GetCitiesWithLetterByContinentID(short continentId)
        {
            string key = string.Format(SR.Cache_City_With_Letter_By_ContinentID, continentId);
            var cities = ByecityCache.Get(key) as List<Letter_City>;
            if (cities == null)
            {
                cities = new List<Letter_City>();
                var allCities = AllCities;
                for (char i = 'A'; i <= 'Z'; i++)
                {
                    string letter = i.ToString();
                    var list = from c in allCities
                               join ct in AllCountries
                                   on c.CountryID equals ct.CountryID
                               where c.ContinentID == continentId && c.Name_Pinyin_Short.StartsWith(letter, StringComparison.OrdinalIgnoreCase)
                               orderby c.Hot
                               select new CountryCityList
                               {
                                   CityName_CN = c.Name_CN,
                                   CityName_EN = c.Name_EN.ToLower().Replace(SR.Space, SR.UnderLine),
                                   CountryName_EN = ct.Name_EN.ToLower().Replace(SR.Space, SR.UnderLine)
                               };
                    if (list.ToList().Count > 0)
                    {
                        cities.Add(new Letter_City
                        {
                            Letter = letter,
                            Cities = list.ToList()
                        });
                    }
                }
                ByecityCache.Max(key, cities);
            }
            return cities;
        }