C＃中，类似native2ascii的方法

public static String native2ascii(String str)
        {
            int code;
            char[] chars = str.ToCharArray();
            StringBuilder sb = new StringBuilder(255);
            for (int i = 0; i < chars.Length; i++)
            {
                char c =chars[i];
                if (c > 255)
                {
                    sb.Append("\\u");
                    code = (c >> 8);
                    string tmp = code.ToString("X");
                    if (tmp.Length == 1) sb.Append("0");
                    sb.Append(tmp);
                    code = (c & 0xFF);
                    tmp = code.ToString("X");
                    if (tmp.Length == 1) sb.Append("0");
                    sb.Append(tmp);
                }
                else
                {
                    sb.Append(c);
                }
 
            } return (sb.ToString());
        }