How to change the VB.NET language version in Visual Studio 2015

Asked 20/8, 2015 at 15:43 Answered 20/8, 2015 at 16:17

Solved vb.net visual-studio visual-studio-2015

In Visual Studio 2015 it is possible to select which version of the C# language is being coded in, as shown here.

I'm looking for the same option for VB.NET - how can I restrict syntax, etc. to old VB.NET versions?

I want to do this so that I stop accidentally using VB 14 features in a project I'm sharing with someone using Visual Studio 2012. I'd rather not spam up my machine with a Visual Studio 2012 install or have to create a new VM for a fairly occasional requirement.

NOTE: I don't want to change the target .NET Framework version.

Bowleg answered 20/8, 2015 at 15:43 Comment(0)

The VB.NET compiler has the /langversion option for this. Also supported by MSBuild. But not by the IDE, that makes it awkward to change it.

Still possible, you have to edit the .vbproj file. Use a text editor, Notepad will do. And copy/paste this snippet, insert it in the 4th line so it is effective for all configurations and platforms:

  <PropertyGroup>
     <LangVersion>12</LangVersion>
  </PropertyGroup>

And double-check that it is effective:

Module Module1
    Sub Main()
        Dim test As String
        Console.WriteLine(NameOf(test))
    End Sub
End Module

Output:

error BC36716: Visual Basic 12.0 does not support 'nameof' expressions.

Well, that works, also flagged by IntelliSense with red squiggles. You probably want to create your own project templates so you don't have to do this over and over again. Use File > Export Template.

Uranium answered 20/8, 2015 at 16:17 Comment(7)

I'll have a test of that. It still seems to be allowing Readonly Auto properties. Do you see that too? – Bowleg 20/8, 2015 at 16:29

I can repro that. Beware that this doesn't get put to the test very often, connect.microsoft.com is a good place to report bugs like this. – Uranium 20/8, 2015 at 16:45

I'll do a test of all the new VB14 features and report on connect. – Bowleg 20/8, 2015 at 19:35

Is raised here if you wan't to give it a vote. Not sure these days if stuff should be logged in Connect or in the open source project areas. – Bowleg 24/8, 2015 at 14:5

I voted. Now tracked in this Roslyn bug, closed as resolved on Jan 21st. – Uranium 15/5, 2016 at 23:58

From what I can see, setting LangVersion in the .proj file works in VS 2015, but not in 2017. – Wiliness 10/5, 2018 at 1:59

Works just fine, checked in version 15.5.6 – Uranium 10/5, 2018 at 7:52

If you're using ReSharper it turns out this is an option:

Left Click on the project in Solution Explorer
Select the Properties Window (not the Project Properties - you want the properties snap in)
Under ReSharper options there is a "VB Language Level" option, which gives options all the way back to VB.NET 8.

I haven't tested how well this works.

Bowleg answered 20/8, 2015 at 16:17 Comment(0)

I don't think this is possible when using VB.

Kolb answered 20/8, 2015 at 16:5 Comment(2)

Do you think it would be possible to reproduce the C# functionality via an Extension to VS? – Bowleg 20/8, 2015 at 16:8

Just noticed that ReSharper can do it - see my answer. – Bowleg 20/8, 2015 at 16:17

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