Deserialize multiple but "different" XML elements with the same name through XmlSerializer class in C#

Question

Given this XML, I need to deserialize it to a class. I'm not sure how to distinguish between the two 'MealPeriod' elements of different types, but of the same name.

<SalesSummary>
  <MealPeriod1>Lunch</MealPeriod1>
  <MealPeriod1Sales>6447.58</MealPeriod1Sales>
  <MealPeriod2>Dinner</MealPeriod2>
  <MealPeriod2Sales>12074.04</MealPeriod2Sales>
  <MealPeriod3>Late-Night</MealPeriod3>
  <MealPeriod3Sales>5156.90</MealPeriod3Sales>
  <MealPeriod4></MealPeriod4>
  <MealPeriod4Sales>0.00</MealPeriod4Sales>
  <MealPeriod1>
    <Interval>
      <Name>10:00am-11:00am</Name>
      <Checks>1</Checks>
      <Guests>1</Guests>
      <AvgCheck>$31.50</AvgCheck>
      <AvgGuest>$31.50</AvgGuest>
      <Sales>$31.50</Sales>
    </Interval>
    <Interval>
      <Name>11:00am-12:00pm</Name>
      <Checks>8</Checks>
      <Guests>29</Guests>
      <AvgCheck>$85.22</AvgCheck>
      <AvgGuest>$23.51</AvgGuest>
      <Sales>$681.75</Sales>
    </Interval>
    <Interval>
      <Name>12:00pm-01:00pm</Name>
      <Checks>27</Checks>
      <Guests>53</Guests>
      <AvgCheck>$48.76</AvgCheck>
      <AvgGuest>$24.84</AvgGuest>
      <Sales>$1,316.58</Sales>
    </Interval>
    <Interval>
      <Name>01:00pm-02:00pm</Name>
      <Checks>17</Checks>
      <Guests>35</Guests>
      <AvgCheck>$58.76</AvgCheck>
      <AvgGuest>$28.54</AvgGuest>
      <Sales>$999.00</Sales>
    </Interval>
    <Interval>
      <Name>02:00pm-03:00pm</Name>
      <Checks>22</Checks>
      <Guests>31</Guests>
      <AvgCheck>$38.99</AvgCheck>
      <AvgGuest>$27.67</AvgGuest>
      <Sales>$857.75</Sales>
    </Interval>
    <Interval>
      <Name>03:00pm-04:00pm</Name>
      <Checks>21</Checks>
      <Guests>44</Guests>
      <AvgCheck>$33.76</AvgCheck>
      <AvgGuest>$16.11</AvgGuest>
      <Sales>$709.00</Sales>
    </Interval>
    <Interval>
      <Name>04:00pm-05:00pm</Name>
      <Checks>32</Checks>
      <Guests>55</Guests>
      <AvgCheck>$57.88</AvgCheck>
      <AvgGuest>$33.67</AvgGuest>
      <Sales>$1,852.00</Sales>
    </Interval>
    <Totals>
      <Checks>128</Checks>
      <Guests>248</Guests>
      <AvgCheck>$50.37</AvgCheck>
      <AvgGuest>$26.00</AvgGuest>
      <Sales>$6,447.58</Sales>
    </Totals>
  </MealPeriod1>
  <MealPeriod2>
    <Interval>
      <Name>05:00pm-06:00pm</Name>
      <Checks>36</Checks>
      <Guests>71</Guests>
      <AvgCheck>$47.85</AvgCheck>
      <AvgGuest>$24.26</AvgGuest>
      <Sales>$1,722.75</Sales>
    </Interval>
    <Interval>
      <Name>06:00pm-07:00pm</Name>
      <Checks>40</Checks>
      <Guests>79</Guests>
      <AvgCheck>$49.01</AvgCheck>
      <AvgGuest>$24.81</AvgGuest>
      <Sales>$1,960.25</Sales>
    </Interval>
    <Interval>
      <Name>07:00pm-08:00pm</Name>
      <Checks>46</Checks>
      <Guests>82</Guests>
      <AvgCheck>$51.03</AvgCheck>
      <AvgGuest>$28.63</AvgGuest>
      <Sales>$2,347.29</Sales>
    </Interval>
    <Interval>
      <Name>08:00pm-09:00pm</Name>
      <Checks>53</Checks>
      <Guests>80</Guests>
      <AvgCheck>$42.04</AvgCheck>
      <AvgGuest>$27.85</AvgGuest>
      <Sales>$2,228.25</Sales>
    </Interval>
    <Interval>
      <Name>09:00pm-10:00pm</Name>
      <Checks>39</Checks>
      <Guests>68</Guests>
      <AvgCheck>$46.94</AvgCheck>
      <AvgGuest>$26.92</AvgGuest>
      <Sales>$1,830.50</Sales>
    </Interval>
    <Interval>
      <Name>10:00pm-11:00pm</Name>
      <Checks>39</Checks>
      <Guests>56</Guests>
      <AvgCheck>$50.90</AvgCheck>
      <AvgGuest>$35.45</AvgGuest>
      <Sales>$1,985.00</Sales>
    </Interval>
    <Totals>
      <Checks>253</Checks>
      <Guests>436</Guests>
      <AvgCheck>$47.72</AvgCheck>
      <AvgGuest>$27.69</AvgGuest>
      <Sales>$12,074.04</Sales>
    </Totals>
  </MealPeriod2>
  <MealPeriod3>
    <Interval>
      <Name>11:00pm-12:00am</Name>
      <Checks>35</Checks>
      <Guests>54</Guests>
      <AvgCheck>$35.80</AvgCheck>
      <AvgGuest>$23.20</AvgGuest>
      <Sales>$1,253.04</Sales>
    </Interval>
    <Interval>
      <Name>12:00am-01:00am</Name>
      <Checks>34</Checks>
      <Guests>45</Guests>
      <AvgCheck>$38.21</AvgCheck>
      <AvgGuest>$28.87</AvgGuest>
      <Sales>$1,299.16</Sales>
    </Interval>
    <Interval>
      <Name>01:00am-02:00am</Name>
      <Checks>23</Checks>
      <Guests>45</Guests>
      <AvgCheck>$40.30</AvgCheck>
      <AvgGuest>$20.60</AvgGuest>
      <Sales>$926.87</Sales>
    </Interval>
    <Interval>
      <Name>02:00am-03:00am</Name>
      <Checks>30</Checks>
      <Guests>59</Guests>
      <AvgCheck>$48.38</AvgCheck>
      <AvgGuest>$24.60</AvgGuest>
      <Sales>$1,451.33</Sales>
    </Interval>
    <Interval>
      <Name>03:00am-04:00am</Name>
      <Checks>1</Checks>
      <Guests>6</Guests>
      <AvgCheck>$226.50</AvgCheck>
      <AvgGuest>$37.75</AvgGuest>
      <Sales>$226.50</Sales>
    </Interval>
    <Totals>
      <Checks>123</Checks>
      <Guests>209</Guests>
      <AvgCheck>$41.93</AvgCheck>
      <AvgGuest>$24.67</AvgGuest>
      <Sales>$5,156.90</Sales>
    </Totals>
  </MealPeriod3>
</SalesSummary>

Here is my class so far. Using multiple XmlElement attributes with the same name isn't going to work, but I'm not sure how to decorate the class properties in a way that will. Any pointers would be much appreciated. Thanks!

public partial class SalesSummary
{
[XmlElement("MealPeriod1")]
public List<SalesSummaryMealPeriod1> MealPeriod1List { get; set; }

[XmlElement("MealPeriod1")]
public string MealPeriod1 { get; set; }

[XmlElement("MealPeriod1Sales")]
public string MealPeriod1Sales { get; set; }

[XmlElement("MealPeriod2")]
public List<SalesSummaryMealPeriod2> MealPeriod2List { get; set; }

[XmlElement("MealPeriod2")]
public string MealPeriod2 { get; set; }

[XmlElement("MealPeriod2Sales")]
public string MealPeriod2Sales { get; set; }

[XmlElement("MealPeriod3")]
public List<SalesSummaryMealPeriod3> MealPeriod3List { get; set; }

[XmlElement("MealPeriod3")]
public string MealPeriod3 { get; set; }

[XmlElement("MealPeriod3Sales")]
public string MealPeriod3Sales { get; set; }

[XmlElement("MealPeriod4")]
public List<SalesSummaryMealPeriod4> MealPeriod4List { get; set; }

[XmlElement("MealPeriod4")]
public string MealPeriod4 { get; set; }

[XmlElement("MealPeriod4Sales")]
public string MealPeriod4Sales { get; set; }
}

Note that the MealPeriodx elements are all fixed.

Answer 1

Each of your <MealPeriodx> elements consists of mixed content, and may contain:

• A string value;
• A sequence of <Interval> elements;
• A <Totals> element.

Building on the answer to Correct XML serialization and deserialization of "mixed" types in .NET by Stefan, you can bind such an element to a c# type as follows:

public class MealPeriod
{
    // A polymorphic array of "mixed" types.
    // See https://stackoverflow.com/questions/2567414/correct-xml-serialization-and-deserialization-of-mixed-types-in-net
    // and the solution by Stefan, https://stackoverflow.com/users/307747/stefan
    // for why this works.
    [XmlElement("Interval", typeof(Interval))]
    [XmlElement("Totals", typeof(Totals))]
    [XmlText(typeof(string))]
    public List<object> Items { get; set; }
}

public class Interval
{
    public string Name { get; set; }
    public int Checks { get; set; }
    public int Guests { get; set; }
    public string AvgCheck { get; set; }
    public string AvgGuest { get; set; }
    public string Sales { get; set; }
}

public class Totals
{
    public int Checks { get; set; }
    public int Guests { get; set; }
    public string AvgCheck { get; set; }
    public string AvgGuest { get; set; }
    public string Sales { get; set; }
}

Then, you can define a root object SalesSummary as follows, where each MealPeriodx property must be a collection of MealPeriod objects, since each <MealPeriodx> appears multiple times in the source XML:

public class SalesSummary
{
    [XmlElement("MealPeriod1")]
    public List<MealPeriod> MealPeriod1 { get; set; }

    [XmlElement("MealPeriod1Sales")]
    public decimal MealPeriod1Sales { get; set; }

    [XmlElement("MealPeriod2")]
    public List<MealPeriod> MealPeriod2 { get; set; }

    [XmlElement("MealPeriod2Sales")]
    public decimal MealPeriod2Sales { get; set; }

    [XmlElement("MealPeriod3")]
    public List<MealPeriod> MealPeriod3 { get; set; }

    [XmlElement("MealPeriod3Sales")]
    public decimal MealPeriod3Sales { get; set; }

    [XmlElement("MealPeriod4")]
    public List<MealPeriod> MealPeriod4 { get; set; }

    [XmlElement("MealPeriod4Sales")]
    public decimal MealPeriod4Sales { get; set; }
}

public static class MealPeriodExtensions
{
    public static string MealPeriodName(this IEnumerable<MealPeriod> mealPeriods)
    {
        if (mealPeriods == null)
            return null;
        return String.Concat(mealPeriods.Where(m => m.Items != null).SelectMany(m => m.Items).OfType<string>());
    }

    public static IEnumerable<T> MealPeriodItems<T>(this IEnumerable<MealPeriod> mealPeriods)
    {
        if (mealPeriods == null)
            return Enumerable.Empty<T>();
        return mealPeriods.Where(m => m.Items != null).SelectMany(m => m.Items).OfType<T>();
    }
}

Then, given a deserialization helper method such as

public static class XmlSerializationHelper
{
    public static T LoadFromXml<T>(this string xmlString, XmlSerializer serial = null)
    {
        serial = serial ?? new XmlSerializer(typeof(T));
        using (var reader = new StringReader(xmlString))
        {
            return (T)serial.Deserialize(reader);
        }
    }
}

You can do:

var summary = xml.LoadFromXml<SalesSummary>();

// Prints:
// MealPeriod1 name: "Lunch"
Console.WriteLine("MealPeriod1 name: \"{0}\"", summary.MealPeriod1.MealPeriodName());

// Prints 
// MealPeriod1 Total Sales: "$6,447.58"
Console.WriteLine("MealPeriod1 Total Sales: \"{0}\"", summary.MealPeriod1.MealPeriodItems<Totals>().Single().Sales);   

Notes:

• If you re-serialize SalesSummary to XML, then the two <MealPeriodx> elements will be shifted to become adjacent to each other. There is no easy way to avoid this using XmlSerializer, other than implementing IXmlSerializable or manually constructing an [XmlAnyElement] surrogate array as shown in this answer.

  Luckily your question only asks for deserialization.

• Interval and Totals have many common properties so you might want to have them share a common base class or interface.

Sample working .Net fiddle here.