Question

I have the following class definition:

public interface IItem{}

public class FirstObject<T, U> : IItem
{
    private readonly Expression<Func<T, U> _field;

    public FirstObject(Expression<Func<T, U> field, U value)
    {
       _field = field;
       Value = value;
    }

    public string FieldName
    {
       get
       {
          var member = _field.Body as MemberExpression;
          if(member != null)
            return member.Member.Name;

          throw new Exception("exception message");
       }
    }

    public U FieldValue { get; private set; }
}

IList<IItem> myList = new List<IItem>();

The IItem interface its only a marker to be able to put the different types of “FirstObject” into the list.

Now I need to iterate the list and get my items back. I definitely need to know both the FieldName and the FieldValue with its specific type. For this and for some other reasons I definitely need to be able to get back the objects’ original type.

Thanks for your help.

UPDATE: I think there is some confusion about what I need to do, so I updated the code and improved on the explanation.

Thank you all for trying to help.

Answer 1

If you want to get property ‘SomeProperty’ form all objects, that implement IItem interface, then I think you should add that property definition to IItem (It’s not just marker iterface, it states this property should exist in every object implementing it)

public interface IItem
{
    object SomeProperty { get; }
}

And implement it explicitly. This will not pollute iterface of your FirstObject objects.

public class FirstObject<T, U> : IItem
{
    public FirstObject(U value)
    {
        SomeProperty = value;
    }

    public U SomeProperty { get; private set; }

    object IItem.SomeProperty
    {
        get { return SomeProperty; }
    }
}

And now you just get that properties by casting each item to IItem interface:

foreach (var item in myList)
{                
   var x = item.SomeProperty; // Voila
}