{"title": "你好

{"title":""你好"}

{"title":"？你好"}

public static class StringExt { 
    // 控制字符
    private static readonly Regex ControlCharRegex = new Regex(@"[\p{C}]", RegexOptions.Compiled);

    /// <summary>
    /// 移除控制字符
    /// </summary>
    public static string RemoveControlChars(this string text) {
        return ControlCharRegex.Replace(text, string.Empty);
    }
}

var outStr = "帶有Unicode的字符串".RemoveControlChars();

/// <summary>
  /// 字符串轉(zhuǎn)Unicode
  /// </summary>
  /// <param name="source">源字符串</param>
  /// <returns>Unicode編碼后的字符串</returns>
  public static string String2Unicode(string source)
  {
   var bytes = Encoding.Unicode.GetBytes(source);
   var stringBuilder = new StringBuilder();
   for (var i = 0; i < bytes.Length; i += 2)
   {  
    stringBuilder.AppendFormat("\\u{0:x2}{1:x2}", bytes[i + 1], bytes[i]);
   }
   return stringBuilder.ToString();
  }
  /// <summary> 
  /// 字符串轉(zhuǎn)為UniCode碼字符串 
  /// </summary> 
  /// <param name="s"></param> 
  /// <returns></returns> 
  public static string StringToUnicode(string s)
  {
   char[] charbuffers = s.ToCharArray();
   byte[] buffer;
   StringBuilder sb = new StringBuilder();
   for (int i = 0; i < charbuffers.Length; i++)
   {
    buffer = System.Text.Encoding.Unicode.GetBytes(charbuffers[i].ToString());
    sb.Append(String.Format("\\u{0:X2}{1:X2}", buffer[1], buffer[0]));
   }
   return sb.ToString();
  }
  /// <summary> 
  /// Unicode字符串轉(zhuǎn)為正常字符串 
  /// </summary> 
  /// <param name="srcText"></param> 
  /// <returns></returns> 
  public static string UnicodeToString(string srcText)
  {
   string dst = "";
   string src = srcText;
   int len = srcText.Length / 6;
   for (int i = 0; i <= len - 1; i++)
   {
    string str = "";
    str = src.Substring(0, 6).Substring(2);
    src = src.Substring(6);
    byte[] bytes = new byte[2];
    bytes[1] = byte.Parse(int.Parse(str.Substring(0, 2), System.Globalization.NumberStyles.HexNumber).ToString());
    bytes[0] = byte.Parse(int.Parse(str.Substring(2, 2), System.Globalization.NumberStyles.HexNumber).ToString());
    dst += Encoding.Unicode.GetString(bytes);
   }
   return dst;
  }