/// <summary>
/// 实现多种编码方式的转换
/// </summary>
/// <param name="str">要转换的字符</param>
/// <param name="From">从哪种方式转换，如UTF-8</param>
/// <param name="To">转换成哪种编码,如GB2312</param>
/// <returns>转换结果</returns>
string ConvertStr(string str, string From, string To)
{
byte[] bs = System.Text.Encoding.GetEncoding(From).GetBytes(str);
bs = System.Text.Encoding.Convert(System.Text.Encoding.GetEncoding(From), System.Text.Encoding.GetEncoding(To), bs);
string res = System.Text.Encoding.GetEncoding(To).GetString(bs);
return res;
}