Implicit type comparison with explicit type - C#

Question

I've got an interesting issue with type comparison. I'm attempting to compare an implied type with an explicit type, to test if something is any sort of collection

var obField = value.GetType().InvokeMember(_stCollectionField, 
                              System.Reflection.BindingFlags.GetProperty, 
                              null, value, null);

if (obField.GetType() != typeof(IEnumerable<object>))
{
    return true;
}

During my testing, I can ensure that obField will turn out to be a collection of objects. However, I'm finding that it will always run inside the check and return true, where instead I wish it to skip past that (becasue the two types are equal.)

A little debugging gives me the type of obField as object {System.Collections.Generic.List<System.DateTime>}.

How can I go about matching that type?

Thanks

If `obField` is of type `List` it clearly is not of type `IEnumerable — Daniel Hilgarth, Jul 06 '11 at 11:49
@Andy: True, but "==" does not mean "is extendable from", it means "is *equal* to" (and the same holds for "!="). Since `List` and `IEnumerable — Heinzi, Jul 06 '11 at 11:54

score 3 · Accepted Answer · edited May 23 '17 at 11:48

3

Use Type.IsAssignableFrom, as used here: Getting all types that implement an interface

For example:

if (typeof(IEnumerable<object>).IsAssignableFrom(obField.GetType())) { ... }

edited May 23 '17 at 11:48

Community

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answered Jul 06 '11 at 11:49

George Duckett

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Addition: This will only work in .NET 4, because covariance for interfaces wasn't available earlier. – Daniel Hilgarth Jul 06 '11 at 11:52
@Andy: If you want to test for any sort of collection then you'd probably be better off comparing against the non-generic `IEnumerable` interface. – LukeH Jul 06 '11 at 13:13

Implicit type comparison with explicit type - C#

1 Answers1