Why does the Nameof operator in VB.NET return the member name with the wrong case?

nameof is one of my favorite operators in C# 6 – it’s a little thing that makes life a little easier.  I use it a lot in Entity Framework 6 with the ForeignKey attribute and when throwing ArgumentExceptions so that I don’t have to have magic strings everywhere.

I discovered some interesting behavior regarding Nameof in VB.NET that I thought took VB.NET’s case insensitivity to the next level:

Class Program
    Sub Main()
        Dim firstNameOf = Nameof(YourClass.FirstName)
        Console.WriteLine(firstNameOf)
        'Output: FirstName
	
        Dim secondNameOf = Nameof(YourClass.fIRsTnAMe)
        Console.WriteLine(secondNameOf)
        'Output: fIRsTnAMe
    End Sub
End Class

Public Class YourClass
    Public Property FirstName As String
End Class

See the difference in outputs?  FirstName versus fIRsTnAMe?  I mean, c’mon, really?  The Nameof operator returns exactly what you type inside of it and not the actual properly cased member name??

This actually caused me a fair bit of grief the other night – I was using Nameof with the ForeignKey attribute in EF and kept getting these odd exceptions where it said it couldn’t find the member called Firstname – and all because I mistyped the casing for the property (FirstName.)

I’ve always had a soft spot for VB.NET – in fact I wrote a whole blog post about it a couple of years ago.  I don’t use it nearly as much anymore – I only have one client who has a VB.NET app.  I gotta say though, it’s weirdness like this that makes me not miss it much, cause that sure is a strange design decision.  It’s one of the very few times that a VB.NET feature is truly not on par with a similar C# one.

(See also: unexpected behavior when using VB.NET’s If() with nullable types: http://stackoverflow.com/questions/10699740/mystery-of-the-if-function-in-vb-net)

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