CODEWITHSUNDEEP
c#c#-6.0.net-4.6
TheColonel26
TheColonel26

Reputation: 2728

Feature 'interpolated strings' is not available in C# 5. Please use language version 6 or greater

There is a similar question to this here but I believe that involves a different cause.

I moved a class from a newer project into an older project. Both were targeting .net 4.6 however after the move I received the following error on build.

Feature 'interpolated strings' is not available in C# 5. Please use language version 6 or greater.

I tried setting my project to build with C# 6 in the properties window with no change.

Upvotes: 33

Views: 29787

Answers (5)

leiflundgren
leiflundgren

Reputation: 2966

The GUI would not let me change the version, but I could change manually in the csproj-file.

<LangVersion>5</LangVersion>
to
<LangVersion>6</LangVersion>

Upvotes: 0

bafsar
bafsar

Reputation: 1108

(It can applicable VS 2019 - .NET Framework 4.8 Web Application projects easily)

I have realized this issue after install DotNetCompilerPlatform v3.6

I have looked for TheColonel26's answer but I couldn't change selected language version:

Advanced Build Setting - Language Version Selection

Appearantly, we can not change selected language version. (For details look here)

After that I have used kfwbird's answer but with changes for newer version:

 <system.codedom>
     <compilers>
         <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=3.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:1659;1699;1701" />
         <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=3.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
     </compilers>
 </system.codedom>

Now it works as should be.

Upvotes: 8

kfwbird
kfwbird

Reputation: 83

Add this to your web.config. It is probably added automatically after installing DotNetCompilerPlatform.

<system.codedom>
  <compilers>
    <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:1659;1699;1701" />
    <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
  </compilers>
</system.codedom>

Upvotes: 5

Navid
Navid

Reputation: 609

Install DotNetCompilerPlatform version 2.1.0

Upvotes: 22

TheColonel26
TheColonel26

Reputation: 2728

I eventually found the place to change it. It seems sometimes when you update your targets framework version this does not get changed. enter image description here

Upvotes: 24

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