创建XML字符串

 public  string  show(string  yourname) 
    { 
        //return  "http://aaaaa"+"欢迎"+yourname;

       //生成xml字符串：
        using (StringWriter sw = new StringWriter())
        {
            XmlTextWriter xtw = new XmlTextWriter(sw);
            xtw.Formatting = Formatting.Indented;
            xtw.WriteStartDocument();

            xtw.WriteStartElement("root");

            //test
            xtw.WriteStartElement("test");
            xtw.WriteString("test content");
            xtw.WriteEndElement();

            //test2
            xtw.WriteStartElement("test2");

            //testSub
            xtw.WriteStartElement("testSub");
            xtw.WriteString("Sub content");
            xtw.WriteEndElement();

            xtw.WriteEndElement();
        

            xtw.WriteEndElement();//root
            xtw.WriteEndDocument();            
          
            string result = sw.ToString();

            return result.Replace("utf-8", "gb2312").Replace("utf-16", "gb2312");
        } 
    }