切换城市的功能实现

　　在做免费婚恋网-圆心网的时候,需要使用切换城市功能，但是这个功能在网上找了一下，没有太多的资料给参考，自己又不想每个城市一个个写连接地址，要知道有上千个连接，一个一个写要写的我崩溃了，于是就想既不想一个一个写，又能节省时间的方法，于是就自己开发了一套城市切换功能的页面，希望能给大家参考。

　　切换城市分为两块，一是根据字母进行查找，比如书苏州直接去S中查找就可以了，另一种是根据省市进行查找，比如说苏州，到江苏省中进行查找。我首先讲一讲对于根据首字母进行查找的实现方法。

做这部分之前的准备是大家必须有省市的资料或是数据，我是将省市的信息存储到数据库，在数据库中有两张表

在通过城市的中文名字获取对应的拼音首字母的时候需要用到汉字与拼音转换功能

/// <summary>           /// 获取汉字的全拼音           /// </summary>           /// <param name="x">传汉字的字符串</param>           /// <returns>汉字的字符串的拼音</returns>           public string GetPinYin(string x)        {            int[] iA = new int[]             {               -20319 ,-20317 ,-20304 ,-20295 ,-20292 ,-20283 ,-20265 ,-20257 ,-20242 ,-20230               ,-20051 ,-20036 ,-20032 ,-20026 ,-20002 ,-19990 ,-19986 ,-19982 ,-19976 ,-19805               ,-19784 ,-19775 ,-19774 ,-19763 ,-19756 ,-19751 ,-19746 ,-19741 ,-19739 ,-19728               ,-19725 ,-19715 ,-19540 ,-19531 ,-19525 ,-19515 ,-19500 ,-19484 ,-19479 ,-19467               ,-19289 ,-19288 ,-19281 ,-19275 ,-19270 ,-19263 ,-19261 ,-19249 ,-19243 ,-19242               ,-19238 ,-19235 ,-19227 ,-19224 ,-19218 ,-19212 ,-19038 ,-19023 ,-19018 ,-19006               ,-19003 ,-18996 ,-18977 ,-18961 ,-18952 ,-18783 ,-18774 ,-18773 ,-18763 ,-18756               ,-18741 ,-18735 ,-18731 ,-18722 ,-18710 ,-18697 ,-18696 ,-18526 ,-18518 ,-18501               ,-18490 ,-18478 ,-18463 ,-18448 ,-18447 ,-18446 ,-18239 ,-18237 ,-18231 ,-18220               ,-18211 ,-18201 ,-18184 ,-18183 ,-18181 ,-18012 ,-17997 ,-17988 ,-17970 ,-17964               ,-17961 ,-17950 ,-17947 ,-17931 ,-17928 ,-17922 ,-17759 ,-17752 ,-17733 ,-17730               ,-17721 ,-17703 ,-17701 ,-17697 ,-17692 ,-17683 ,-17676 ,-17496 ,-17487 ,-17482               ,-17468 ,-17454 ,-17433 ,-17427 ,-17417 ,-17202 ,-17185 ,-16983 ,-16970 ,-16942               ,-16915 ,-16733 ,-16708 ,-16706 ,-16689 ,-16664 ,-16657 ,-16647 ,-16474 ,-16470               ,-16465 ,-16459 ,-16452 ,-16448 ,-16433 ,-16429 ,-16427 ,-16423 ,-16419 ,-16412               ,-16407 ,-16403 ,-16401 ,-16393 ,-16220 ,-16216 ,-16212 ,-16205 ,-16202 ,-16187               ,-16180 ,-16171 ,-16169 ,-16158 ,-16155 ,-15959 ,-15958 ,-15944 ,-15933 ,-15920               ,-15915 ,-15903 ,-15889 ,-15878 ,-15707 ,-15701 ,-15681 ,-15667 ,-15661 ,-15659               ,-15652 ,-15640 ,-15631 ,-15625 ,-15454 ,-15448 ,-15436 ,-15435 ,-15419 ,-15416               ,-15408 ,-15394 ,-15385 ,-15377 ,-15375 ,-15369 ,-15363 ,-15362 ,-15183 ,-15180               ,-15165 ,-15158 ,-15153 ,-15150 ,-15149 ,-15144 ,-15143 ,-15141 ,-15140 ,-15139               ,-15128 ,-15121 ,-15119 ,-15117 ,-15110 ,-15109 ,-14941 ,-14937 ,-14933 ,-14930               ,-14929 ,-14928 ,-14926 ,-14922 ,-14921 ,-14914 ,-14908 ,-14902 ,-14894 ,-14889               ,-14882 ,-14873 ,-14871 ,-14857 ,-14678 ,-14674 ,-14670 ,-14668 ,-14663 ,-14654               ,-14645 ,-14630 ,-14594 ,-14429 ,-14407 ,-14399 ,-14384 ,-14379 ,-14368 ,-14355               ,-14353 ,-14345 ,-14170 ,-14159 ,-14151 ,-14149 ,-14145 ,-14140 ,-14137 ,-14135               ,-14125 ,-14123 ,-14122 ,-14112 ,-14109 ,-14099 ,-14097 ,-14094 ,-14092 ,-14090               ,-14087 ,-14083 ,-13917 ,-13914 ,-13910 ,-13907 ,-13906 ,-13905 ,-13896 ,-13894               ,-13878 ,-13870 ,-13859 ,-13847 ,-13831 ,-13658 ,-13611 ,-13601 ,-13406 ,-13404               ,-13400 ,-13398 ,-13395 ,-13391 ,-13387 ,-13383 ,-13367 ,-13359 ,-13356 ,-13343               ,-13340 ,-13329 ,-13326 ,-13318 ,-13147 ,-13138 ,-13120 ,-13107 ,-13096 ,-13095               ,-13091 ,-13076 ,-13068 ,-13063 ,-13060 ,-12888 ,-12875 ,-12871 ,-12860 ,-12858               ,-12852 ,-12849 ,-12838 ,-12831 ,-12829 ,-12812 ,-12802 ,-12607 ,-12597 ,-12594               ,-12585 ,-12556 ,-12359 ,-12346 ,-12320 ,-12300 ,-12120 ,-12099 ,-12089 ,-12074               ,-12067 ,-12058 ,-12039 ,-11867 ,-11861 ,-11847 ,-11831 ,-11798 ,-11781 ,-11604               ,-11589 ,-11536 ,-11358 ,-11340 ,-11339 ,-11324 ,-11303 ,-11097 ,-11077 ,-11067               ,-11055 ,-11052 ,-11045 ,-11041 ,-11038 ,-11024 ,-11020 ,-11019 ,-11018 ,-11014               ,-10838 ,-10832 ,-10815 ,-10800 ,-10790 ,-10780 ,-10764 ,-10587 ,-10544 ,-10533               ,-10519 ,-10331 ,-10329 ,-10328 ,-10322 ,-10315 ,-10309 ,-10307 ,-10296 ,-10281               ,-10274 ,-10270 ,-10262 ,-10260 ,-10256 ,-10254              };            string[] sA = new string[]             {              "a","ai","an","ang","ao"               ,"ba","bai","ban","bang","bao","bei","ben","beng","bi","bian","biao","bie","bin"             ,"bing","bo","bu"               ,"ca","cai","can","cang","cao","ce","ceng","cha","chai","chan","chang","chao","che"             ,"chen","cheng","chi","chong","chou","chu","chuai","chuan","chuang","chui","chun"             ,"chuo","ci","cong","cou","cu","cuan","cui","cun","cuo"               ,"da","dai","dan","dang","dao","de","deng","di","dian","diao","die","ding","diu"             ,"dong","dou","du","duan","dui","dun","duo"               ,"e","en","er"               ,"fa","fan","fang","fei","fen","feng","fo","fou","fu"               ,"ga","gai","gan","gang","gao","ge","gei","gen","geng","gong","gou","gu","gua","guai"             ,"guan","guang","gui","gun","guo"               ,"ha","hai","han","hang","hao","he","hei","hen","heng","hong","hou","hu","hua","huai"             ,"huan","huang","hui","hun","huo"               ,"ji","jia","jian","jiang","jiao","jie","jin","jing","jiong","jiu","ju","juan","jue"             ,"jun"               ,"ka","kai","kan","kang","kao","ke","ken","keng","kong","kou","ku","kua","kuai","kuan"             ,"kuang","kui","kun","kuo"               ,"la","lai","lan","lang","lao","le","lei","leng","li","lia","lian","liang","liao","lie"             ,"lin","ling","liu","long","lou","lu","lv","luan","lue","lun","luo"               ,"ma","mai","man","mang","mao","me","mei","men","meng","mi","mian","miao","mie","min"             ,"ming","miu","mo","mou","mu"               ,"na","nai","nan","nang","nao","ne","nei","nen","neng","ni","nian","niang","niao","nie"             ,"nin","ning","niu","nong","nu","nv","nuan","nue","nuo"               ,"o","ou"               ,"pa","pai","pan","pang","pao","pei","pen","peng","pi","pian","piao","pie","pin","ping"             ,"po","pu"               ,"qi","qia","qian","qiang","qiao","qie","qin","qing","qiong","qiu","qu","quan","que"             ,"qun"               ,"ran","rang","rao","re","ren","reng","ri","rong","rou","ru","ruan","rui","run","ruo"               ,"sa","sai","san","sang","sao","se","sen","seng","sha","shai","shan","shang","shao","she"             ,"shen","sheng","shi","shou","shu","shua","shuai","shuan","shuang","shui","shun","shuo","si"             ,"song","sou","su","suan","sui","sun","suo"               ,"ta","tai","tan","tang","tao","te","teng","ti","tian","tiao","tie","ting","tong","tou","tu"             ,"tuan","tui","tun","tuo"               ,"wa","wai","wan","wang","wei","wen","weng","wo","wu"               ,"xi","xia","xian","xiang","xiao","xie","xin","xing","xiong","xiu","xu","xuan","xue","xun"               ,"ya","yan","yang","yao","ye","yi","yin","ying","yo","yong","you","yu","yuan","yue","yun"               ,"za","zai","zan","zang","zao","ze","zei","zen","zeng","zha","zhai","zhan","zhang","zhao"             ,"zhe","zhen","zheng","zhi","zhong","zhou","zhu","zhua","zhuai","zhuan","zhuang","zhui"             ,"zhun","zhuo","zi","zong","zou","zu","zuan","zui","zun","zuo"            };            byte[] B = new byte[2];            string s = "";            char[] c = x.ToCharArray();            for (int j = 0; j < c.Length; j