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

Question

The following line does not compile when I put in a Razor View.

var extPropLookupNameCompania = $"extension_{SettingsHelper.ClientId.Replace("-", "")}_{"Compania"}";

However in the controller the same line works perfectly fine.

Why I cant user string interpolation on the razor views? or Maybe I need to configure something?

Alexander Schmidt · Answer 1 · 2015-08-06T14:55:46.507

3

You have to encapsulate it with braces like this:

EDIT: I updated because there was a missing curly.

var extPropLookupNameCompania = $("{extension_{SettingsHelper.ClientId.Replace("-", "")}_{"Compania"}");

I tried the following successfully:

 @($"It is {DateTime.Now}")

edited Aug 06 '15 at 14:55

answered Aug 06 '15 at 00:02

Alexander Schmidt

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I get this: Severity Code Description Project File Line Error CS0019 Operator '-' cannot be applied to operands of type 'string' and 'string' – Luis Valencia Aug 06 '15 at 13:50
I added a curly brace at the beginning. Is it better now? You have to check the thing by yourself. Thats why I added the principle sample. – Alexander Schmidt Aug 06 '15 at 14:56
nop, that doesnt work, I still get the same error from first comment, your line works perfectly fine, but mine doesnt. – Luis Valencia Aug 11 '15 at 20:53
How about replacing `{"Compania"}`with `{Compania}`? – Alexander Schmidt Aug 13 '15 at 10:13

score 3 · Accepted Answer · answered Sep 03 '15 at 12:11

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If you are experiencing this error in a .NET Framework 4.5.1 project, upgrading to 4.5.2 solves the problem.

answered Sep 03 '15 at 12:11

omufeed

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If the error does not go away, installing the following NuGet package may help. `PM> Install-Package Microsoft.CodeDom.Providers.DotNetCompilerPlatform` – omufeed Nov 03 '15 at 13:57
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Here's some detail on the codeDom package: http://dusted.codes/using-csharp-6-features-in-aspdotnet-mvc-5-razor-views – tlbignerd Dec 15 '15 at 20:20
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I'm on .NET Framework 4.6 and I still get this error. – Giles Roberts Jan 11 '16 at 10:25
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Real answer is in comments by @omufeed or tlbignerd not in content labeled as answers. – Saulius Feb 03 '17 at 11:57
What worked for me was installing the Microsoft.CodeDom.Providers.DotNetCompilerPlatform – Cătălin Rădoi Apr 20 '17 at 16:19

score 0 · Answer 3 · answered Aug 30 '17 at 23:35

The key is to see the compilerOptions="/langversion:6 portion of the following in your web.config. Without it I got errors trying to use string interpolation inside a .cshtml file.

  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:6 /nowarn:1659;1699;1701" />
      <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:14 /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
    </compilers>
  </system.codedom>

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

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