Question

I’ve been wrestling with this problem for a few hours now and I’m beginning to think I’m too far down the rabbit hole. Before I give up entirely, I’m hoping someone might be able to shed some light on this for me…

public class Object
{
    public Object()
    {
        Properties = new List<Property>();
    }

    public int Id { get; set; }
    public IList<Property> Properties { get; set; }
}

public class Property
{
    public string Name { get; set; }
    public dynamic Value { get; set; }
}

    [Test]
    public void ShouldBeAbleToGroupAnArrayOfObjectsByASpecificProperty()
    {
        // Arrange
        var objects = new List<Object>();
        var doorObject = new Object() {
                                 Properties = new List<Property>() {new Property() {Name = "Level", Value = "Level 1"}}
                             };

        var wallobject = new Object() {
                                 Properties = new List<Property>() { new Property() { Name = "Level", Value = "Level 2" } }
                             };

        var chairObject = new Object() {
                                  Properties = new List<Property>() { new Property() { Name = "Level", Value = "Level 2" } }
                              };

        objects.Add(doorObject);
        objects.Add(wallobject);
        objects.Add(chairObject);

        // Act
        var groupBy = objects.SelectMany(obj => obj.Properties).GroupBy(props => props.Value);

        // Assert
        Assert.That(groupBy.Count(), Is.EqualTo(2));
    }

This test passes, but the problem is that I’m returning an array of Properties. I’m attempting to get an array of Objects. Is what I’m trying to do possible?

Answer 1

How about this:

objects.GroupBy(obj => obj.Properties.First().Value);

or

objects.GroupBy(obj => obj.Properties.First(p => p.Name == "Level").Value);