Accessing elements of types with indexers using expression trees

Suppose I have a type like this:

class Context
{
    SomeType[] Items { get; set; }
}

I want to be able to access specific Items elements using expression trees. Suppose I need an element at index 0. I can do it like below, where everything works as expected:

var type = typeof (Context);
var param = Expression.Parameter(typeof (object));
var ctxExpr= Expression.Convert(param, context);    
var proInfo = type.GetProperty("Items");

Expression.ArrayIndex(Expression.Property(ctxExpr, proInfo), Expression.Constant(0));

If I change the context type to contain .NET provided List<SomeType>, instead of array, i.e.

class Context
{
    List<SomeType> Items { get; set; }
}

the same expression results in following error:

System.ArgumentException: Argument must be array at System.Linq.Expressions.Expression.ArrayIndex(Expression array, Expression index)

My question is, how to write respective expression which can access an item under appropriate index of List<>, or better - of any collection declaring indexer? E.g. is there is some way to detect, and convert such a collection to an array of appropriate types using expression trees?