You must add a reference to assembly "netstandard, Version=2.0.0.0

📢 How to Fix the "Add a Reference to Assembly 'netstandard, Version=2.0.0.0" Error in ASP.NET MVC Web App 🛠️

Are you facing the dreaded error message in your ASP.NET MVC Web App, asking you to add a reference to assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'? 😱 Don't worry, we've got you covered! In this blog post, we'll address common issues, provide easy solutions, and help you get back on track.

The Scenario:

You've recently upgraded some NuGet packages and suddenly started encountering the following error during runtime:

CS0012: The type 'System.Object' is defined in an assembly that is not referenced. You must add a reference to assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'.

The error occurs in your main view, specifically in a line where you're using @Html.ActionLink. Your ASP.NET MVC Web App is targeting the .NET Framework 4.6.1, and you're only using the full Windows .NET Framework, not .NET Core.

The Problem:

You might be wondering why your app is asking for a reference to netstandard when you're only using the Windows .NET Framework. The issue stems from the upgraded NuGet packages, which might have introduced a dependency on .NET Standard.

🚀 Easy Solutions:

1. Check the project compatibility: First, ensure that your ASP.NET MVC Web App is targeting the correct .NET Framework - in this case, 4.6.1. To verify this, right-click on your project, go to Properties, and navigate to the Application tab. Confirm that the Target framework is set to .NET Framework 4.6.1.

2. Review the NuGet packages: Check the NuGet packages you recently upgraded and their compatibility with the .NET Framework 4.6.1. Some packages might have a dependency on .NET Standard, which could trigger the error message.

3. Update the problematic packages: If you find any packages causing the issue, try updating them to their latest version. Sometimes, newer versions resolve compatibility issues with the .NET Framework.

4. Clean and Rebuild: Make sure to clean your solution and rebuild it after updating the NuGet packages. This can help resolve any conflicts or inconsistencies.

📜 Additional Troubleshooting Steps:

If the easy solutions outlined above didn't fix the issue, you can consider taking the following steps:

• Review the project files: Check your .csproj file or any other configuration files where the reference to netstandard might be present. Ensure that there are no explicit references or package dependencies pointing to the wrong version.

• Inspect the installed frameworks: Double-check your development machine and server to ensure that the required frameworks and SDKs are correctly installed. In this case, verify that the .NET Framework 4.6.1 and the .NET Core SDK 2.0 are present on your machine.

• Examine compiler directives: If you're using any conditional compilation directives in your code, be cautious that they are not inadvertently causing the error. Verify that these directives are correctly targeting the desired framework.

📢 Your Call to Action: Join the Conversation! 🗣️

Are you still facing challenges with the "Add a Reference to Assembly 'netstandard, Version=2.0.0.0" error? Or, have you discovered an alternative solution that worked for you? We'd love to hear from you! Share your experiences, tips, or questions in the comments below, and let's help each other overcome this hurdle. Happy coding! 😊

References:

• Link to .csproj gist

That's it, folks! We hope this guide helped you resolve the troublesome error and get back to coding with ease. Remember, sharing is caring, so feel free to share this post with your fellow developers who might be struggling with the same issue. Stay tuned for more exciting tech tips and tricks! 👩‍💻👨‍💻