Question

I’ve got a List<Component> collection (Component is a custom class) with a single element that inherits from XTYPE.

But for some reason this doesn’t work:

X = (XTYPE)Components.Single((c) => c is XTYPE);

I get an InvalidOperationException with the message “Sequence contains no matching element”
But if I put in a breakpoint at that line and do this it returns true:

Components[0] is XTYPE

Furthermore if I do this it returns true:

Components[0].GetType().BaseType.BaseType == typeof(XTYPE)

Help.

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OK, so I added a few checks into my code…

        foreach (Component c in Components)
            Console.WriteLine(c.GetType().BaseType.BaseType == typeof(Bridge));
        if (Components.Count == 0)
            throw new Exception("No components");
        if (!(Components[0].GetType().BaseType.BaseType == typeof(Bridge)))
            throw new Exception("Not bridge.");

False gets written to the console, but the type names are the same.
This is probably DLL hell. And now requires a diff set of information to answer the question.

I think you guys have helped me move toward my solution.

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Further explanation: the Component in question was instantiated via reflection from a separate instance of the DLL that has XTYPE in it. So now we’ve got two XTYPEs but they technically aren’t the same type because they’ve got a diff typehandle.

The debugger wasn’t checking in the right context so it thought the types were the same. But it was wrong.

Answer 1

the Component in question was instantiated via reflection from a separate instance of the DLL that has XTYPE in it. So now we’ve got two XTYPEs but they technically aren’t the same type because they’ve got a diff typehandle.

The debugger wasn’t checking in the right context so it thought the types were the same. But it was wrong.