Determine if an object implements IEnumerable of (T)

I was recently attending a .NET conference when a programmer popped up a question. How do I make sure that my type implements IEnumerable<T>

Here's how:


    protected void CheckInterfaceImpl(Type someType)


        Type[] listInterfaces = someType.GetType().GetInterfaces();

        foreach (Type t in listInterfaces)


            if (t.GetGenericTypeDefinition() == typeof(IEnumerable<>))   


                // Implements IEnumerable<T>




                // Does not Implement IEnumerable<T>






    Protected Sub CheckInterfaceImpl(ByVal someType As Type)

        Dim listInterfaces() As Type = someType.GetType.GetInterfaces()

        For Each t As Type In listInterfaces

            If t.GetGenericTypeDefinition() Is GetType(IEnumerable(Of )) Then

                ' Implements IEnumerable<T>


                ' Does not Implement IEnumerable<T>

            End If


        Next t

    End Sub

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About The Author

Suprotim Agarwal
Suprotim Agarwal, ASP.NET Architecture MVP (Microsoft Most Valuable Professional) works as an Architect Consultant and provides consultancy on how to design and develop Web applications.

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1 comment:

Anonymous said...

This code does not work at all.
1. someType.GetType() returns typeof(Type).
2. GetGenericTypeDefinition() is only valid for generic types, it will throw InvalidOpertaionException as soon as it reaches first non-generic interface.

Here is my solution (C#):

static bool IsIEnumerableT (Type someType)
return someType.GetInterface (typeof(IEnumerable<>).FullName) != null;