获取含有中文字符串的长度

var Mystring = "钓鱼岛是中国的 I love China";
var MyDate = new ASCIIEncoding();
byte[] MyBytes = MyDate.GetBytes(Mystring);
var myLength = 0;
for (int i = 0; i <= MyBytes.Length - 1; i++)
{
  if (MyBytes[i] == 63)//判断是否为汉字或全脚符号
  {
   myLength++;
  }
  myLength++;
}