Question

I have several templated objects that all implement the same interface:

I.E.

MyObject<datatype1> obj1;
MyObject<datatype2> obj2;
MyObject<datatype3> obj3;

I want to store these objects in a List… I think I would do that like this:

private List<MyObject<object>> _myList;

I then want to create a function that takes 1 parameter, being a datatype, to see if an object using that datatype exists in my list…. sorta clueless how to go about this. In Pseudo code it would be:

public bool Exist(DataType T)
{
   return (does _myList contain a MyObject<T>?);
}

Some Clarification….

My interface is IMyObject<T>, my objects are MyObject<T>. I have a new class MyObjectManager which I need to have a List of MyObject<T> stored within. I need a function to check if a MyObject<T> exists in that list. The type T are datatypes which were auto-generated using T4…. POCO classes from my Entity Data Model.

Answer 1

You can make a generic function:

public bool Exists<T>() where T : class {
    return _myList.OfType<MyObject<T>>().Any();
}

Note that this requires that you know T at compile-time.

If all you have is a System.Type object at runtime, you’ll need to use reflection:

public bool Exists(Type t) {
    var objectOfT = typeof(MyObject<>).MakeGenericType(t);

    return _myList.Any(o => o.GetType() == objectOfT);
}

Note, however, that a List<MyObject<object>> cannot hold a MyObject<SomeType>.
You need to change the list to a List<object>, or make MyObject implement or inherit a non-generic type and make the list contain that type.