Using LINQ to loop through inner class properties in outer class collection and group by outer class properties

Question

Leveraging off the Q&As dealing with looping through an object's properties (Loop Through An Objects Properties In C# and Using LINQ to loop through inner class properties in outer class collection), where you have:

a collection of Class1 objects (i.e. listObj1)
each Class1 contains properties and a collection of Class2 objects (i.e. dictObj2)

How would you:

Efficiently determine the properties of the inner class (Class2)
loop through the the properties of the inner class (Class2)
loop through the collection of Class1 objects (listObj1) selecting all instances of the the Class2 property
output the collection of Class2 property (e.g. the first iteration would return a collection of MeasurementA, one from each Class1 object).
and group the collection by Class1.PropertyA and Class1.PropertyB

Please find below a rough map of the classes involved.

I have been trying to use a LINQ query without success. The answer provided by Konrad Kokosa is most of the way there. Any ideas or guidance would be greatly appreciated.

class MainClass {
  List<Class1> listObj1
}

class Class1 {
  // a number of fields including...
  int PropertyA { get; set; }
  int PropertyB { get; set; }
  Dictionary<int, Class2> dictObj2 { get; set; }
}

class Class2 {
  // a number of fields all of type double...
  double MeasurementA { get; set; }
  double MeasurementB { get; set; }
  double MeasurementC { get; set; }
}

score 0 · Answer 1 · answered Sep 27 '14 at 06:21

Just Loop:

foreach(var cls1 in listObj1)
{
    int tempA = cls1.PropertyA;
    foreach(var cls2 in cls1.dictObj2)
    {
         double tempB = cls2.MeasurementB;
    }
}

Filtered/Efficient Loop:

foreach(var cls1 in listObj1.Where(c1=> c1.PropertyA > 5 && c1.PropertyB > 3))
{
    int tempA = cls1.PropertyA;
    foreach(var cls2 in cls1.dictObj2.Where(c2=> c2.MeasurementA >= 10))
    {
         double tempB = cls2.MeasurementB;
    }
}

Using LINQ to loop through inner class properties in outer class collection and group by outer class properties

1 Answers1