WebService的返回值中少了一个int型的属性，向大家请教。

[shi_hang_nk]

下面的WebService方法返回一个RetObjs类型的对象，它继承了List但增加了一个属性。
public class WebService_ReturnObject : WebService
{
public class RetObj{}
public class RetObjs : List <RetObj>
{
private int _count;
public int RecordCount
{
get { return _count; }
set { _count = value; }
}
}

[WebMethod()]
[XmlInclude(typeof(RetObjs))]
public RetObjs getRetObjs()
{
RetObjs ret = new RetObjs();
ret.RecordCount = 100;

ret.AddRange(new RetObj[] { new RetObj(), new RetObj() });
return ret;
}
}

但我在VS Studio中通过View in Browser执行的结果中没有这个属性，请问各位是什么原因，如何增加上？
<?xml version= "1.0 " encoding= "utf-8 " ?>
- <ArrayOfRetObj xmlns:xsi= "http://www.w3.org/2001/XMLSchema-instance " xmlns:xsd= "http://www.w3.org/2001/XMLSchema " xmlns= "http://tempuri.org/ ">
<RetObj />
<RetObj />
</ArrayOfRetObj>

[r_swordsman]

由于 List<T> 实现了 IList<T>, ICollection<T>, IEnumerable<T>, IList, ICollection, IEnumerable 这些接口，
而默认情况下，实现 ICollection 或 IEnumerable 的类 只有集合会被序列化，而公共属性却不会。

[shi_hang_nk]

那怎样加上公共属性呢？

我又换了一种方式，这次有属性了，但是返回的XML多了一层元素

public class ListBase<T>
{
public ListBase()
{
Records = new List<T>();
}

private int _count;
[XmlAttribute("RecordCount")]
public int RecordCount
{
get { return _count; }
set { _count = value; }
}

//[XmlArrayItem(ElementName = "Record", Type = typeof(Employee))]
//[XmlArray(ElementName = "Records")]
private List<T> _records;
public List<T> Records
{
get { return _records; }
set { _records = value; }
}

public void AddRange(T[] array)
{
Records.AddRange(array);
}
}

public class Employees2 : ListBase<Employee>
{
}

[WebMethod()]
public Employees2 getRetObjs2()
{
Employees2 ret = new Employees2();
ret.RecordCount = 2;

ret.AddRange(new Employee[] { new Employee(), new Employee() });
return ret;
}

返回：
<?xml version="1.0" encoding="utf-8" ?>
- <Employees2 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" RecordCount="2" xmlns="http://tempuri.org/">
- <Records>
<Employee />
<Employee />
</Records>
</Employees2>

如何去掉Records，让Employees2下面直接就是Employee，同时还保留RecordCount这个公共属性？

[r_swordsman]

呵，默认就是这样了。自己重写了，例如

        void WriteXml(System.Xml.XmlWriter writer)
        {
            writer.WriteStartElement("Attributes");
            writer.WriteAttributeString("RecordCount", _count.ToString());
            writer.WriteAttributeString("Other", "value");
            writer.WriteEndElement();

            XmlSerializer xmlser = new XmlSerializer(typeof(RetObj), "http://myserver/mynamespace");

            for (int i = 0; i < Count; i++) xmlser.Serialize(writer, this[i]);
        }

结果（加如 RetObj 有 Age 属性，且默认行为）：

<?xml version="1.0" encoding="utf-8"?>
<RetObjs xmlns="http://tempuri.org/">
  <Attributes RecordCount="100" Other="value" />
  <RetObj xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://myserver/mynamespace">
    <Age>0</Age>
  </RetObj>
  <RetObj xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://myserver/mynamespace">
    <Age>0</Age>
  </RetObj>
</RetObjs>