Nlog: Upgrade code/projects to C#7 / vs2017

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Upgrade projects and code:

• [ ] use ?.
• [x] use lambda expressions - https://github.com/NLog/NLog/pull/2361
• [x] prefix privates with _ - core: https://github.com/NLog/NLog/pull/2327
• and others
• no functional changes.

[ie-zero]

I would like very much to start working on this but I cannot figure out what needs to be done on the configuration of AppVeyor to accept C# 6 syntax.

I tried the adding the following in various combinations
os: Visual Studio 2015

install:
  - set PATH=C:\Program Files (x86)\MSBuild\14.0\Bin;%PATH% 

and
image: Visual Studio 2015

Would it be possible for someone more experienced with MSBuild to assist please?

PS. If someone would like to see what it has been attempted see at https://github.com/ie-zero/NLog/tree/UpgradeCode_FileInfoExt

[304NotModified]

Strange, I have more c#6 projects building. Will look at it soon.

[304NotModified]

The msbuild project needed a change. (horrible thing).

See https://github.com/NLog/NLog/commit/98af2d994fbc938f2b4baaa7ec06c82b24a0bea0 (not in master) and

https://ci.appveyor.com/project/nlog/nlog/build/4.4.4040

probably all projects needs an update.

[304NotModified]

NB: We have to be sure that this won't give use many conflicts on the coreCLR branch

[ie-zero]

Nice one!

[304NotModified]

@ie-zero are you using Resharper? A lot of these points could be done for the full project in a few clicks.

[ie-zero]

No I do not. I will leave it to someone else than.

[304NotModified]

Or get a Free OSS license of Resharper (https://www.jetbrains.com/buy/opensource/?product=resharper)

You are doing great work @ie-zero ! I you like it, I could add you to the NLog organization!

[304NotModified]

This is done :)