How will I do a property drill down?

Question

How will I know if an object instance is a property or a sub property of another object instance?

for example I have this class structure:

public class Car
{
      public Manufacturer Manufacturer {get;set;}
}

public class Manufacturer
{
      public List<Supplier> {get;set;}
}

public class Supplier
{
      string SupplierName {get;set;}
}

And I only have two instances, the Car and the SupplierName; Using PropertyInfo in Reflection, How can I Implement a method such as

bool IsPropertyOrSubPropertyOf(object ObjectInstance, object TargetObejectInstance)

used as

IsPropertyOrSubPropertyOf(SupplierNameInstance, CarInstance)

this method will return true if the CarInstance's Property Manufacturer has a Supplier that has a SupplierName SupplierNameInstance

Answer 1

You shouldn't need to use reflection for the particular example you describe:

bool IsPropertyOrSubPropertyOf(Supplier supplierInstance, Car carInstance)
{
    return carInstance.Manufacturer.Suppliers.Contains(supplierInstance);
}

(By the way, you missed out the name of the List<Supplier> property in your Manufacturer class. I've assumed that it's actually called Suppliers in my code above.)

Answer 2

Does this do what your looking for? Sorry if its not the cleanest - you will probably want to add some null checks in there aswell.

    private bool IsPropertyOrSubPropertyOf(Object Owner, Object LookFor)
 {

  if (Owner.Equals(LookFor))
  {
   // is it a property if they are the same?
   // may need a enum rather than bool
   return true;
  }

  PropertyInfo[] Properties = Owner.GetType().GetProperties();

  foreach (PropertyInfo pInfo in Properties)
  {
   var Value = pInfo.GetValue(Owner, null);

   if (typeof(IEnumerable).IsAssignableFrom(Value.GetType()))
   {
    // Becomes more complicated if it can be a collection of collections
    foreach (Object O in (IEnumerable)Value)
    {
     if (IsPropertyOrSubPropertyOf(O, LookFor))
      return true;
    }
   }
   else
   {
    if (IsPropertyOrSubPropertyOf(Value, LookFor))
    {
     return true;
    }
   }

  }
  return false;
 }

---

Edit: I just noticed that if LookFor is IEnumerable then you may end up with an issue, will leave that to you to sort out ;)