How to deserialize an XML array containing multiple types of elements in C#

c#, c#-4.0, deserialization, xml

Solution

There are two ways to do this; the first is to do something like:

[XmlArray("players")]
[XmlArrayItem("skater", Type=typeof(Skater))]
[XmlArrayItem("goalie", Type=typeof(Goalie))]
public List<SomeCommonBaseClass> Players { get; set; }

which maps the two element types inside a single collection. Worst case, `SomeCommonBaseClass` could be `object`:

[XmlArray("players")]
[XmlArrayItem("skater", Type=typeof(Skater))]
[XmlArrayItem("goalie", Type=typeof(Goalie))]
public List<object> Players { get; set; }

The second is to make `<players>` map to a wrapper object:

[XmlElement("players")]
public Players Players { get;set;}
...
public class Players
{
    [XmlElement("skater")]
    public List<Skater> Skaters {get;set;}

    [XmlElement("goalie")]
    public List<Goalie> Goalies {get;set;}
}

Which to choose depends on the circumstance; the latter allows things like "at most one goalie", by changing it to:

    [XmlElement("goalie")]
    public Goalie Goalie {get;set;}

Problem

I'm trying to deserialize the following file: ``` <league> <players> <skater> <name>Wayne Stamkos</name> <goals>23</goals> <assists>34</assists> </skater> <skater> <name>Sidney Lindros</name> <goals>41</goals> <assists>44</assists> </skater> <goalie> <name>Martin Roy</name> <wins>15</wins> <losses>12</losses> </goalie> <skater> <name>Paul Forsberg</name> <goals>21</goals> <assists>51</assists> </skater> <goalie> <name>Roberto Rinne</name> <wins>18</wins> <losses>23</losses> </goalie> </players> </league> ``` With the following code: ``` namespace ConsoleApplication2 { [XmlRoot("league")] public class League { [XmlArray("players")] [XmlArrayItem("skater")] public List<Skater> skaters { get; set; } [XmlArrayItem("goalie")] public List<Goalie> goalies { get; set; } } public class Skater { [XmlElement("name")] public string Name; [XmlElement("goals")] public int Goals; [XmlElement("assists")] public int Assists; } public class Goalie { [XmlElement("name")] public string Name; [XmlElement("wins")] public int Wins; [XmlElement("losses")] public int Losses; } class Program { static void Main(string[] args) { using (FileStream reader = new FileStream(@"C:\Temp\test.xml", FileMode.Open, FileAccess.Read)) { var ser = new XmlSerializer(typeof(League)); League league = (League)ser.Deserialize(reader); } } } } ``` I'm expecting to get back a League object containing a Skaters list with 3 elements and a Goalies list with 2 elements. I do get the expected Skaters list but the Goalies list is empty. What am I doing wrong?

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