Visual Studio 2017 (15.x) supports C# 7, but what about Visual Studio 2015 (14.x)?
How can I use C# 7 with it?
You can replace the compiler shipped with Visual Studio for a C# 7-enabled version by installing the Nuget package Microsoft.Net.Compilers:
Referencing this package will cause the project to be built using the
specific version of the C# and Visual Basic compilers contained in the
package, as opposed to any system installed version.
There is no indication that I can see on the package page as to whether this is officially supported in Visual Studio 2015. My not-thorough tests so far indicate that it works but not painlessly - C# 7 code compiles, but is underlined with the red squiggly line which indicates a syntax error:
Note that you will also need to install the Nuget package System.ValueTuple to use the new C# 7 value tuples features.
In my case, installing just Microsoft.Net.Compilers didn't work. Instead, I had to do the following:
Install Microsoft.CodeDom.Providers.DotNetCompilerPlatform for the project (Tools => NuGet Package Manager => Manage Nuget Packages for Solution...) and install Microsoft.CodeDom.Providers.DotNetCompilerPlatform.Install the latest Microsoft.Net.Compilers for the project
Install any other NuGet package for the latest C# feature you want to use. In my case, my goal was to use Tuples, so I installed System.ValueTuple and worked fine.
But still note that C# codes which are not known by Visual Studio 2015 default compiler will still have red squiggles underneath.
Related
Is Roslyn the default compiler in Visual Studio 2017?
I found this article
which tells that Roslyn is not the default compiler and you should install Nuget packages to enable Roslyn.
Nuget packages:
Microsoft.CodeDom.Providers.DotNetCompilerPlatform
Microsoft.Net.Compilers
But I also saw an answer on stackoverflow that says, Roslyn is the default compiler starting from VS 2015.
And when i am install that nuget packages, it's creating a new folder in /bin
with name 'roslyn'
Yes, Roslyn is the default compiler in Visual Studio.
In the article you link, it only says you need to install it separately if you are trying to use it without Visual Studio:
To date, Roslyn has remained a part of Visual Studio 2015 and is installed together with it. Roslyn is a part of Visual Studio 2017 as well. It has been released in March 2017.
However, Roslyn is not included in the .NET Framework. Even in the .NET Framework 4.6 version, the traditional csc.exe and vbc.exe compilers are included. This is done for it to be compatible with previous .NET Framework versions.
To install Roslyn compilers without installing Visual Studio, you need to download and install Microsoft Build Tools. Roslyn can also be downloaded from Github, then you can compile and get binary files csc.exe and vbc.exe, which can be accessed from the command line.
You would typically only need those NuGet packages if you were building an application or service for compiling code (or similar), which is what that article is about. That is, when your application is actually using Roslyn at runtime to process code, rather than itself being built with Roslyn.
Solution consists of 2 dll libraries, 1 console app and 1 web app. Only the last project, the web one, uses Microsoft.Net.Compilers NuGet package. Package has been updated to version 2.3.0 now, what means C# 7.1 and VB 15.3.
source: Roslyn NuGet packages
As 3 other projects do not have Microsoft.Net.Compilers NuGet package installed, what Roslyn compiler and C# version do they use?
I use VS.Net 2017 15.2 with .NET Framework 4.7, so I would guess it shall C#7.0, but still Microsoft.Net.Compilers in version 2.2 should be installed there, but is not.
The Microsoft.Net.Compilers package overrides (by setting properties in your project file) the default version of Roslyn included with MSBuild / Visual Studio.
Regular class libraries that don't reference it are compiled using the Roslyn build included with your version of Visual Studio & MSBuild.
I would like to install protobuf-net using NutGet and Visual Studio 2012.
However, if I try to install it, I got the following error message from NuGet :
'protobuf-net' already has a dependency defined for
'NETStandard.Library'.
I have tried to install NETStandard.Library but there is an error :
The 'NETStandard.Library 1.6.0' package requires NuGet client version
'2.12' or above, but the current NuGet version is '2.8.60318.667'.
I also tried to update NuGet (by uninstalling it then re-install), but it seems with Visual Studio 2012 it is stuck to 2.8 version.
I don't have Visual Studio 2012 to test, but I wonder if this is due to the way Nuget now works with the .Net Core dependencies. It should work if you install an older version of protobuf-net. You can see that the older version doesn't mention .NETStandard as a dependency. To do this, from the package manager console, type this:
Install-Package protobuf-net -Version 2.0.0.668
I found that this protobuf-portable-net works on .NET 4.5 for VS 2013 and has the same version number as above: 2.0.0.668. It's the same author and might be a better approach than intentionally installing an old version of a newer package.
I am using VS 2013 and .Net 4.5/4.6. I am not getting this error message:
The 'System.Collections 4.0.10' package requires NuGet client version '3.0' or above, but the current NuGet version is '2.8.60723.765'.
My understanding is that this is due to a ddl that use a higher version of .Net. Just curious is there a way to fix this (e.g. determine the responsibel dll[s])?
Those packages are primarily designed for .NET Core ecosystem,
https://www.nuget.org/packages/System.Collections/4.0.10
That means it should not be used for .NET 4.5 and Visual Studio 2013. I guess that's probably why Microsoft only releases NuGet 3.* for Visual Studio 2015. It makes sense to avoid polluting Visual Studio 2013 users with the brand new bits.
A workaround is to specify a version of a NuGet your client is actually compatible with.
i.e.
System.Collections Version=x.x.x picking of course a slightly older version than the latest one.
You need to update your nuget package manager.
You can download the latest version over here:
https://visualstudiogallery.msdn.microsoft.com/4ec1526c-4a8c-4a84-b702-b21a8f5293ca
I was going through the latest features introduced in C# 6.0 and just followed an example of auto property initializer,
class NewSample
{
public Guid Id { get; } = Guid.NewGuid();
}
but my IDE did not recognize the syntax.
I am wondering how I could enable C# 6.0 in Visual Studio 2013. The Target framework I am using is 4.5.1.
Under VS2013 you can install the new compilers into the project as a nuget package. That way you don't need VS2015 or an updated build server.
https://www.nuget.org/packages/Microsoft.Net.Compilers/
Install-Package Microsoft.Net.Compilers
The package allows you to use/build C# 6.0 code/syntax. Because VS2013 doesn't natively recognize the new C# 6.0 syntax, it will show errors in the code editor window although it will build fine.
Using Resharper, you'll get squiggly lines on C# 6 features, but the bulb gives you the option to 'Enable C# 6.0 support for this project' (setting saved to .DotSettings).
As mentioned by #stimpy77: for support in MVC Razor views you'll need an extra package (for those that don't read the comments)
Install-Package Microsoft.CodeDom.Providers.DotNetCompilerPlatform
If you want full C# 6.0 support, you'll need to install VS2015.
Information for obsoleted prerelease software:
According to this it's just a install and go for Visual Studio 2013:
In fact, installing the C# 6.0 compiler from this release involves little more than installing a Visual Studio 2013 extension, which in turn updates the MSBuild target files.
So just get the files from https://github.com/dotnet/roslyn and you are ready to go.
You do have to know it is an outdated version of the specs implemented there, since they no longer update the package for Visual Studio 2013:
You can also try April's End User Preview, which installs on top of Visual Studio 2013.
(note: this VS 2013 preview is quite out of date, and is no longer updated)
So if you do want to use the latest version, you have to download the Visual Studio 2015.
A lot of the answers here were written prior to Roslyn (the open-source .NET C# and VB compilers) moving to .NET 4.6. So they won't help you if your project targets, say, 4.5.2 as mine did (inherited and can't be changed).
But you can grab a previous version of Roslyn from https://www.nuget.org/packages/Microsoft.Net.Compilers and install that instead of the latest version. I used 1.3.2. (I tried 2.0.1 - which appears to be the last version that runs on .NET 4.5 - but I couldn't get it to compile*.) Run this from the Package Manager console in VS 2013:
PM> Install-Package Microsoft.Net.Compilers -Version 1.3.2
Then restart Visual Studio. I had a couple of problems initially; you need to set the C# version back to default (C#6.0 doesn't appear in the version list but seems to have been made the default), then clean, save, restart VS and recompile.
Interestingly, I didn't have any IntelliSense errors due to the C#6.0 features used in the code (which were the reason for wanting C#6.0 in the first place).
* version 2.0.1 threw error The "Microsoft.CodeAnalysis.BuildTasks.Csc task could not be loaded from the assembly Microsoft.Build.Tasks.CodeAnalysis.dll. Could not load file or assembly 'Microsoft.Build.Utilities.Core, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. Confirm that the declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask.
UPDATE One thing I've noticed since posting this answer is that if you change any code during debug ("Edit and Continue"), you'll like find that your C#6.0 code will suddenly show as errors in what seems to revert to a pre-C#6.0 environment. This requires a restart of your debug session. VERY annoying especially for web applications.
It worth mentioning that the build time will be increased for VS 2015 users after:
Install-Package Microsoft.Net.Compilers
Those who are using VS 2015 and have to keep this package in their projects can fix increased build time.
Edit file packages\Microsoft.Net.Compilers.1.2.2\build\Microsoft.Net.Compilers.props and clean it up. The file should look like:
<Project DefaultTargets="Build"
xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
</Project>
Doing so forces a project to be built as it was before adding Microsoft.Net.Compilers package
It is possible to use full C# 6.0 features in Visual Studio 2013 if you have Resharper.
You have to enable Resharper Build and voilá!
In Resharper Options -> Build - enable Resharper Build and in "Use MSBuild.exe version" choose "Latest Installed"
This way Resharper is going to build your C# 6.0 Projects and will also not underline C# 6.0 code as invalid.
I am also using this although I have Visual Studio 2015 because:
Unit Tests in Resharper don't work for me with Visual Studio 2015 for some reason
VS 2015 uses a lot more memory than VS 2013.
I am putting this here, as I was looking for a solution for this problem for some time now and maybe it will help someone else.
It seems there's some misunderstanding. So, instead of trying to patch VS2013 here's and answer from a Microsoft guy: https://social.msdn.microsoft.com/Forums/vstudio/en-US/49ba9a67-d26a-4b21-80ef-caeb081b878e/will-c-60-ever-be-supported-by-vs-2013?forum=roslyn
So, please, read it and install VS2015.