List 序列化问题

[wyb0026]

调用总是错 Lsit保存多种类难道不行

 private void button1_Click(object sender, EventArgs e)
        {

            List<object> list = new List<object>();
            list.Add(new A());
            list.Add(new B());
            list.SaveToXml(@"D:\aaa.xml");
        }

这样就没问题

 List<A> list = new List<A>();

但是我要A,B混在 有什么解决方法


序列化主程序总是错

 public static void SaveToXml(this object obj, string filname)
        {
            System.Xml.Serialization.XmlSerializer xs = new System.Xml.Serialization.XmlSerializer(obj.GetType());
            using (FileStream stream = new FileStream(filname, FileMode.Create))
            {
                System.Xml.XmlWriterSettings settings = new System.Xml.XmlWriterSettings()
                {
                    Indent = true
                };
                using (System.Xml.XmlWriter writer = System.Xml.XmlWriter.Create(stream, settings))
                {
                    xs.Serialize(writer, obj);
                    
                }
            }
        }