引用：http://blog.csdn.net/u011511086/article/details/72865006 

/// <summary>  
/// 字符串转Unicode  
/// </summary>  
/// <param name="source">源字符串</param>  
/// <returns>Unicode编码后的字符串</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>    
/// 字符串转为UniCode码字符串    
/// </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字符串转为正常字符串    
/// </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;  
}