C#中文和UNICODE字符转换方法

        /// <summary>
        /// 将Unicode编码转换为汉字字符串
        /// </summary>
        /// <param name="str">Unicode编码字符串</param>
        /// <returns>汉字字符串</returns>
        public static string ToGB2312(string str)
        {
            StringBuilder sb = new StringBuilder();
            MatchCollection mCollection2 = Regex.Matches(str, "([\w]+)|(\\u([\w]{4}))");
            if (mCollection2 != null && mCollection2.Count > 0)
            { 
                foreach (Match m2 in mCollection2)
                {
                    string v = m2.Value;
                    if (v.StartsWith("\u"))
                    {
                        string word = v.Substring(2);
                        byte[] codes = new byte[2];
                        int code = System.Convert.ToInt32(word.Substring(0, 2), 16);
                        int code2 = System.Convert.ToInt32(word.Substring(2), 16);
                        codes[0] = (byte)code2;
                        codes[1] = (byte)code;
                        sb.Append(Encoding.Unicode.GetString(codes));
                    }
                    else
                    {
                        sb.Append(v);
                    }
                } 
            }
            return sb.ToString();
        }

        //可以包括其他字符       
        public string uncode(string str)
        {
            string outStr = "";
            Regex reg = new Regex(@"(?i)//u([0-9a-f]{4})");
            outStr = reg.Replace(str, delegate(Match m1)
            {
                return ((char)Convert.ToInt32(m1.Groups[1].Value, 16)).ToString();
            });
            return outStr;
        }