Serializing multiple nested XmlArrays in C#

Question

I am trying to do serialize a class that contains a List with nested Tuples with arrays of DateTimes as keys and doubles as values.

Below is a basic version of the code:

Class:

[XmlRoot("Foo")]
public class Foo
{
    [XmlArray("Pairs")]
    [XmlArrayItem(typeof(Tuple<DateTime[], double>), ElementName = "Pair")]
    [XmlArrayItem(typeof(DateTime), ElementName = "DateRange"), XmlArrayItem(typeof(double), ElementName = "Value")]
    public List<Tuple<DateTime[], double>> pairs;
}

Main:

class Program
{
    static void Main(string[] args)
    {
        Foo f = new Foo();
        f.pairs = new List<Tuple<DateTime[], double>>();

        f.pairs.Add(
            new Tuple<DateTime[], double>(
                new DateTime[2]{
                    new DateTime(2014,1,1),
                    new DateTime(2014,1,3),
                },
                1.1
            ));

        f.pairs.Add(
            new Tuple<DateTime[], double>(
                new DateTime[2]{
                    new DateTime(2014,2,1),
                    new DateTime(2014,2,3),
                },
                2.2
            ));

        System.Xml.Serialization.XmlSerializer writer =
            new System.Xml.Serialization.XmlSerializer(typeof(Foo));

        System.IO.StreamWriter file = new System.IO.StreamWriter(
            @"C:/Users/x/Desktop/test.xml");


    }
}

I am getting a reflecting error and I think the issue is that I am not using the attributes correctly as there are too many nested arrays.

Is there a way to make this work, or would I need to create separate serializable classes and nest those within one another?

Answer 1

The error I'm getting is not about nested arrays. When you look at the Inner exceptions you will eventually arrive at:

System.Tuple`2[System.DateTime[],System.Double] cannot be serialized 
because it does not have a parameterless constructor.

Why I could not serialize a tuple in C#?

So I am afraid you will have to change your designs ...