Question

I have a class Parent which has as property Items that is a List(of Child)

If I use this code

Parallel.ForEach()(parent.Items,
            Sub(item)
                item.DoSomething()
            End Sub)

I get a compiler warning No overload for method ForEach() accepts this count of arguments

If I change the code to

Parallel.ForEach(of Child)(parent.Items,
            Sub(item)
                item.DoSomething()
            End Sub)

it works.

However, in c# I can just write

Parellel.ForEach(parent.Items, item =>
    {
        item.DoSomething();
    });

Why does VB not infer in this case?

Answer 1

In your first VB example you have an extra set of parentheses so you are calling .ForEach wih no parameters. Remove them and it will work:

Parallel.ForEach(parent.Items,
         Sub(item)
            item.DoSomething()
         End Sub)