Windows Server 2012 R2的IIS 8.5站点无法定位.NET 4.5.2报错求助

Hey there, let's work through this interpolation string error you're hitting. Even though you've confirmed .NET 4.5.2 is installed on your Windows Server 2012 R2 machine, it seems your IIS site is still behaving like it's targeting .NET 4.0. Here's how to fix that:

• Check your Application Pool's .NET CLR Version
  .NET 4.5+ is an in-place upgrade of .NET 4.0, so the CLR version number stays v4.0.30319—but you need to make sure your site's app pool is configured to use this, not an older version.

  1. Open IIS Manager, navigate to your site, right-click it > Manage Website > Advanced Settings to note the assigned Application Pool name.
  2. Switch to the Application Pools node, find your pool, right-click > Advanced Settings.
  3. Under the General section, confirm .NET CLR Version is set to v4.0.30319 (not "No Managed Code" or v2.0). Also ensure Managed Pipeline Mode is set to Integrated (unless your app specifically requires Classic mode).

• Update web.config to Target .NET 4.5.2
  Your site's web.config needs explicit settings to tell ASP.NET to use 4.5.2 features (like C# 6's interpolation strings). Open your site's root web.config and verify these nodes exist:

  <!-- In the <system.web> section -->
  <compilation debug="true" targetFramework="4.5.2" />
  <httpRuntime targetFramework="4.5.2" />
  

  If these lines are missing, add them. This ensures the runtime leverages 4.5.2 framework capabilities.

• Ensure C# 6 Compiler Support
  Interpolation strings are a C# 6 feature, so you need to make sure your site is configured to compile with C# 6 or higher. Add or update the <system.codedom> section in web.config:

  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs"
        type="Microsoft.CSharp.CSharpCodeProvider, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
        compilerOptions="/langversion:6" />
    </compilers>
  </system.codedom>
  

  If you're publishing from Visual Studio, also double-check your project's Advanced Build Settings (right-click project > Properties > Build > Advanced) to ensure Language version is set to C# 6 or later before republishing.

• Verify .NET 4.5.2 is Properly Installed
  Even though you mentioned it's installed, let's confirm:

  1. Open Control Panel > Programs and Features and look for "Microsoft .NET Framework 4.5.2" in the list.
  2. Alternatively, run this command in Command Prompt to check the registry value for .NET 4.5.2:

     reg query "HKLM\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full" /v Release
     

     For .NET 4.5.2, the Release value should be 379893.

• Restart Your App Pool and Site
  After making these changes, right-click your Application Pool > Recycle, then right-click your site > Restart. This ensures all new configuration settings take effect.

If you still hit errors after these steps, feel free to share the exact error message you're seeing—this will help narrow things down further!

内容的提问来源于stack exchange，提问作者Brendan Gooden