在C＃中获取对类型中所有类型对象的引用

Question

Say I have a class with reference variables to some objects of type Foo. Say I now want to get a list of all of these variables dynamically, meaning if I add a new one that one will also be in the list.

I have tried using reflection, but I am not very experienced with it, so I think that is the right way but I'm not completely sure.

public class Foo() {
    public void Setup() {
        // Runs some code
    }
}

public class MyClass() {
    public Foo a;
    public Foo b;
    public Foo c;
    public Foo d;
    public Foo e;

    // Current constructor, does what I want but in a non-elegant way
    MyClass() {

        Foo[] foos= new Foo[] {
            a,
            b,
            c,
            d,
            e
        };
        foreach(Foo foo in foos) {
            foo.Setup();
        }
    }

    // The constructor I want, with GetAllMembersOfType<T>() dynamically
    // returning new objects as I add them to the class later
    MyClass() {

        Foo[] foos = GetAllMembersOfType<Foo>();
        foreach(Foo foo in foos) {
            foo.Setup();
        }
    }
}

How could I create a method like GetAllMembersOfType<T>() ? Or at least a way to call Setup() on all member variables of type Foo ?

Answer 1

Using reflection to get all private and public fields of a type, your constructor will become this:

public class MyClass() 
{
    public Foo a;
    public Foo b;
    public Foo c;
    public Foo d;
    public Foo e;

    MyClass() 
    {
        Foo[] foos = GetType().GetFields(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public)
            .Where(fieldInfo => fieldInfo.FieldType.Equals(typeof(Foo)))
            .Select(fieldInfo => fieldInfo.GetValue(this))
            .Cast<Foo>()
            .ToArray();

        foreach(Foo foo in foos) 
        {
            foo.Setup();
        }
    }
}

But this fields might not be initialized. Maybe it's more convenient to call Setup() on instantiation either as an external call or constructor call.

Answer 2

@BionicCode answer works perfectly, but you can also invoke the method with reflection if you want. It would look something like this:

public MyClass()
{
  MethodInfo method = typeof(Foo).GetMethod("Setup", BindingFlags.Instance |
    BindingFlags.NonPublic | BindingFlags.Public);

  foreach (FieldInfo f in GetType().GetFields(BindingFlags.Instance |
    BindingFlags.NonPublic | BindingFlags.Public)
    .Where(fieldInfo => fieldInfo.FieldType.Equals(typeof(Foo))))
  {
    method.Invoke(f.GetValue(this), null);
  }
}