public static bool CheckStateKey(string taxcode)
        {
            int sum =  0 ;
            int key;
            string KeyWord1 = "1234567", KeyWord2 = "7123456", KeyWord3 = "3456789", KeyWord4 = "9345678";
            if (int.Parse(taxcode) <  30000000  || int.Parse(taxcode) >  60000000 )
            {
                for (int i =  0 ; i <  7 ; i++)
                {
                    sum = sum + int.Parse(taxcode.Substring(i,  1 )) * (int.Parse(KeyWord1.Substring(i,  1 )));
                }
            }
            else if (int.Parse(taxcode) >  30000000  || int.Parse(taxcode) <  60000000 )
            {
                for (int i =  0 ; i <  7 ; i++)
                {
                    sum = sum + int.Parse(taxcode.Substring(i,  1 )) * (int.Parse(KeyWord2.Substring(i,  1 )));
                }
            }
            key = sum %  11 ;
            if (key >  9 )
            {
                sum =  0 ;
                if (int.Parse(taxcode) <  30000000  || int.Parse(taxcode) >  60000000 )
                {
                    for (int i =  0 ; i <  7 ; i++)
                    {
                        sum = sum + int.Parse(taxcode.Substring(i,  1 )) * (int.Parse(KeyWord3.Substring(i,  1 )));
                    }
                }
                else if (int.Parse(taxcode) >  30000000  || int.Parse(taxcode) <  60000000 )
                {
                    for (int i =  0 ; i <  7 ; i++)
                    {
                        sum = sum + int.Parse(taxcode.Substring(i,  1 )) * (int.Parse(KeyWord4.Substring(i,  1 )));
                    }
                }
                key = sum %  11 ;
                if (key >  9 )
                    key =  0 ;
            }
            string NewTaxCode = taxcode.Substring( 0 ,  7 ) + key.ToString();

            return (NewTaxCode == taxcode);
        }