18位身份证验证精华代码

private  string  CheckCidInfo(string  cid)
{
string[]  aCity  =  new  string[]{null,null,null,null,null,null,null,null,null,null,null,"北京","天津","河北","山西","内蒙古",null,null,null,null,null,"辽宁","吉林","黑龙江",null,null,null,null,null,null,null,"上海","江苏","浙江","安微","福建","江西","山东",null,null,null,"河南","湖北","湖南","广东","广西","海南",null,null,null,"重庆","四川","贵州","云南","西藏",null,null,null,null,null,null,"陕西","甘肃","青海","宁夏","新疆",null,null,null,null,null,"台湾",null,null,null,null,null,null,null,null,null,"香港","澳门",null,null,null,null,null,null,null,null,"国外"};
double  iSum=0;

string  info="";
System.Text.RegularExpressions.Regex  rg  =  new  System.Text.RegularExpressions.Regex(@"^d{17}(d|x)$");
System.Text.RegularExpressions.Match  mc  =  rg.Match(cid);
if(!mc.Success)
{
return  "";
}     
cid  =  cid.ToLower();
cid  =  cid.Replace("x","a");
if(aCity[int.Parse(cid.Substring(0,2))]==null)
{
return  "非法地区";
}
try
{
DateTime.Parse(cid.Substring(6,4)+"-"+cid.Substring(10,2)+"-"+cid.Substring(12,2));
}
catch
{
return  "非法生日";
}
for(int  i=17;i>=0;i--)
{       
iSum  +=(System.Math.Pow(2,i)%11)*int.Parse(cid[17-i].ToString(),System.Globalization.NumberStyles.HexNumber);
}
if(iSum%11!=1)
return("非法证号");
   
return(aCity[int.Parse(cid.Substring(0,2))]+","+cid.Substring(6,4)+"-"+cid.Substring(10,2)+"-"+cid.Substring(12,2)+","+(int.Parse(cid.Substring(16,1))%2==1?"男":"女"));
 
}