How do I fix: Resolving circular dependencies?

Step 1: Use the Dependency Injection debugger to identify and resolve circular dependencies between classes. This can be done by using the Visual Studio built-in debugger or a third-party tool.Step 2: Review the class diagram and identify any circular references, then refactor the code to avoid thes

Software⏱️ 3 min read📅 2026-06-03

How to Fix: Dependency Injection error: Unable to resolve service for type while attempting to activate, while class is registered

Q: How do I fix: 🚀 How to Resolve This Issue Registering the correct repository implementation?

Step 1: In the Startup.cs file, ensure that the BloggerRepository class is correctly registered with the DI container by adding the following code: services.AddTransient();Step 2: Verify that the correct assembly or namespace containing the BloggerRepository class is included in the project referenc

Learn how to fix: Dependency Injection error: Unable to resolve service for type while attempting to activate, while class is registered.

Quick Answer: Try checking your system settings or restarting.

📋 Table of Contents

💡 Why You Are Getting This Error
🚀 How to Resolve This Issue
💡 Conclusion

The error 'InvalidOperationException: Unable to resolve service for type 'WebApplication1.Data.BloggerRepository' while attempting to activate 'WebApplication1.Controllers.BlogController'' occurs when the .NET Core MVC application fails to inject the required BloggerRepository instance into the BlogController.

This issue affects developers who use Dependency Injection and Repository Pattern in their .NET Core applications, causing frustration due to the inability to resolve the service type.

💡 Why You Are Getting This Error

The primary cause of this error is a mismatch between the registered repository type and the required type in the controller. In this case, the BloggerRepository interface is registered but not correctly resolved as the actual implementation.
An alternative reason for this issue could be a circular dependency or a missing configuration in the DI container.

🚀 How to Resolve This Issue

Registering the correct repository implementation

Step 1: In the Startup.cs file, ensure that the BloggerRepository class is correctly registered with the DI container by adding the following code: services.AddTransient();
Step 2: Verify that the correct assembly or namespace containing the BloggerRepository class is included in the project references.
Step 3: Check for any circular dependencies between classes and resolve them before proceeding.

Resolving circular dependencies

Step 1: Use the Dependency Injection debugger to identify and resolve circular dependencies between classes. This can be done by using the Visual Studio built-in debugger or a third-party tool.
Step 2: Review the class diagram and identify any circular references, then refactor the code to avoid these dependencies.

💡 Conclusion

By following these steps, developers should be able to resolve the 'InvalidOperationException: Unable to resolve service for type' error in their .NET Core MVC applications using Dependency Injection and Repository Pattern.

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