Search code examples
c#xmlserializationwebrequest

How can I deserialize an XML response to an object when I only need a child element of the XML?


I have the following XML that I am getting back from a WebRequest:

<?xml version="1.0" encoding="UTF-8"?>
<search>
  <total_items>5</total_items>
  <page_size>10</page_size>
  <page_count>1</page_count>
  <page_number>1</page_number>
  <page_items></page_items>
  <first_item></first_item>
  <last_item></last_item>
  <search_time>0.044</search_time>
  <events>
    <event id="E0-001-053379749-0">
      <title>Antibalas</title>
      <url>http://test.com</url>
      <description>stuff</description>
      <start_time>2013-01-30 20:00:00</start_time>
      <stop_time></stop_time>
      <tz_id></tz_id>
      <tz_olson_path></tz_olson_path>
      <tz_country></tz_country>
      <tz_city></tz_city>
      <venue_id>V0-001-000189211-5</venue_id>
      <venue_url>http://blah.com</venue_url>
      <venue_name>Troubadour</venue_name>
      <venue_display>1</venue_display>
      <venue_address>9081 Santa Monica Boulevard</venue_address>
      <city_name>West Hollywood</city_name>
      <region_name>California</region_name>
      <region_abbr>CA</region_abbr>
      <postal_code>90069</postal_code>
      <country_name>United States</country_name>
      <country_abbr2>US</country_abbr2>
      <country_abbr>USA</country_abbr>
      <latitude>34.0815917</latitude>
      <longitude>-118.3892462</longitude>
      <geocode_type>EVDB Geocoder</geocode_type>
      <all_day>0</all_day>
      <recur_string></recur_string>
      <calendar_count></calendar_count>
      <comment_count></comment_count>
      <link_count></link_count>
      <going_count></going_count>
      <watching_count></watching_count>
      <created>2012-12-24 11:40:43</created>
      <owner>evdb</owner>
      <modified>2013-01-14 21:08:04</modified>
      <performers>
        <performer>
          <id>P0-001-000000517-4</id>
          <url>http://test.com</url>
          <name>Antibalas</name>
          <short_bio>Afro-beat / Funk / Experimental</short_bio>
          <creator>jfisher</creator>
          <linker>evdb</linker>
        </performer>
      </performers>
      <image>
        <url>http://s4.evcdn.com/images/small/I0-001/000/070/311-5.jpeg_/antibalas-11.jpeg</url>
        <width>48</width>
        <height>48</height>
        <caption></caption>
        <thumb>
          <url>http://s4.evcdn.com/images/thumb/I0-001/000/070/311-5.jpeg_/antibalas-11.jpeg</url>
          <width>48</width>
          <height>48</height>
        </thumb>
        <small>
          <url>http://s4.evcdn.com/images/small/I0-001/000/070/311-5.jpeg_/antibalas-11.jpeg</url>
          <width>48</width>
          <height>48</height>
        </small>
        <medium>
          <url>http://s4.evcdn.com/images/medium/I0-001/000/070/311-5.jpeg_/antibalas-11.jpeg</url>
          <width>128</width>
          <height>128</height>
        </medium>
      </image>
      <privacy>1</privacy>
      <calendars></calendars>
      <groups></groups>
      <going></going>
    </event>
  </events>
</search>

I have created the following classes:

public class EventSearch
{
    public int total_items { get; set; }
    public int page_size { get; set; }
    public int page_count { get; set; }
    public int page_number { get; set; }
    public int page_items { get; set; }
    public string first_item { get; set; }
    public string last_item { get; set; }
    public string search_time { get; set; }
    public List<Event> events { get; set; }
}

public class Event
{
    public string id { get; set; }
    public string title { get; set; }
    public string url { get; set; }
    public string description { get; set; }
    public DateTime start_time { get; set; }
    public string venue_id { get; set; }
    public string venue_url { get; set; }
    public string venue_name { get; set; }
    public string venue_address { get; set; }
    public string city_name { get; set; }
    public string region_name { get; set; }
    public string region_abbr { get; set; }
    public string postal_code { get; set; }
    public string country_name { get; set; }
    public string country_abbr { get; set; }
    public string country_abbr2 { get; set; }
    public double latitude { get; set; }
    public double longitude { get; set; }
    public List<Performer> performers { get; set; }
    public EventImage image { get; set; }
}

public class Performer
{
    public string id { get; set; }
    public string url { get; set; }
    public string name { get; set; }
    public string short_bio { get; set; }
}

public class EventImage
{
    public string url { get; set; }
    public int width { get; set; }
    public int height { get; set; }
    public Image thumb { get; set; }
    public Image small { get; set; }
    public Image medium { get; set; }
}

public class Image
{
    public string url { get; set; }
    public int width { get; set; }
    public int height { get; set; }
}

In the method that I am calling, I want to return a list of events. Here's what I have so far, which is giving me the error:

was not expected.

Code:

var request = WebRequest.Create(url);
var response = request.GetResponse();

if (((HttpWebResponse)response).StatusCode == HttpStatusCode.OK)
{
    // Get the stream containing content returned by the server.
    Stream dataStream = response.GetResponseStream();
    // Open the stream using a StreamReader.
    StreamReader reader = new StreamReader(dataStream);

    XmlSerializer serializer = new XmlSerializer(typeof(EventSearch));
    EventSearch deserialized = (EventSearch)serializer.Deserialize(reader);

    return deserialized.events;
}

I'm not sure what to do next. Do I need to annotate my classes?


Solution

  • Yes, you will need to add some Attributes to your classes to map the xml elements to your objects.

    This should work, However I had to change a few things, The DateTime in the Xml is in the wrong fromat so I made it a string(you can parse as needed), also page_items is an int but it is an empty element in the xml, you wont be able to deserialize this, you will have to change to a string if it has a chance of being empty.

    [XmlType("search")]
    public class EventSearch
    {
        public int total_items { get; set; }
        public int page_size { get; set; }
        public int page_count { get; set; }
        public int page_number { get; set; }
       // public int? page_items { get; set; }
        public string first_item { get; set; }
        public string last_item { get; set; }
        public string search_time { get; set; }
        public List<Event> events { get; set; }
    }
    
    [XmlType("event")]
    public class Event
    {
        [XmlAttribute("id")]
        public string id { get; set; }
        public string title { get; set; }
        public string url { get; set; }
        public string description { get; set; }
        public string start_time { get; set; }
        public string venue_id { get; set; }
        public string venue_url { get; set; }
        public string venue_name { get; set; }
        public string venue_address { get; set; }
        public string city_name { get; set; }
        public string region_name { get; set; }
        public string region_abbr { get; set; }
        public string postal_code { get; set; }
        public string country_name { get; set; }
        public string country_abbr { get; set; }
        public string country_abbr2 { get; set; }
        public double latitude { get; set; }
        public double longitude { get; set; }
        public List<Performer> performers { get; set; }
        public EventImage image { get; set; }
    }
    
    [XmlType("performer")]
    public class Performer
    {
        public string id { get; set; }
        public string url { get; set; }
        public string name { get; set; }
        public string short_bio { get; set; }
    }
    
    [XmlType("image")]
    public class EventImage
    {
        public string url { get; set; }
        public int width { get; set; }
        public int height { get; set; }
        public Image thumb { get; set; }
        public Image small { get; set; }
        public Image medium { get; set; }
    }
    
    [XmlType("thumb")]
    public class Image
    {
        public string url { get; set; }
        public int width { get; set; }
        public int height { get; set; }
    }
    

    I tested directly from file using:

    using (FileStream stream = new FileStream("C:\\Test.xml", FileMode.Open))
    {
        XmlSerializer serializer = new XmlSerializer(typeof(EventSearch));
        EventSearch deserialized = (EventSearch)serializer.Deserialize(stream);
    }
    

    But your Stream from the Webresponce should work the same as the FileStream

    Hope this helps :)