C#: Dependency Injection Error: Unable To Resolve Service For Type While Attempting To Activate, While Class Is Registered

There are a few possible reasons for this error message in C#. Here are some common scenarios and potential solutions:

  1. Missing Registration: Make sure the class/interface you are trying to inject is registered in the dependency injection container. If you are using a container like Microsoft.Extensions.DependencyInjection, ensure that you have added the necessary services using the appropriate method (AddScoped, AddSingleton, etc.).

  2. Incorrect Lifetime: Check if the registered service has the correct lifetime specified. If the service is registered as scoped or transient, and you are trying to inject it into a singleton service, you may encounter this error. In such cases, register the service with a lifetime compatible with the consuming class.

  3. Auto-discovery Issues: If you are using an assembly scanning feature or an auto-discovery mechanism provided by a DI container, confirm that the necessary class/interface is included in the scanned assembly or configured correctly.

  4. Missing Constructor: Ensure that the class being registered has a public constructor. Dependency injection requires a constructor that can be resolved, either through parameterless constructor or by injecting other dependencies.

  5. Interface/Implementation Mismatch: Verify that the registered service matches the type being injected. Sometimes, this error occurs when the registered service and the expected type for injection do not match precisely.

  6. Circular Dependency: Circular dependencies among classes can cause issues with the dependency injection container. Inspect your class dependencies and check if there are any circular dependencies that could be causing this error.

By considering the above situations and making the necessary adjustments, you should be able to resolve the "Unable to resolve service for type" error in a C# dependency injection scenario.

About the Author Rex

I'm a passionate tech blogger with an insatiable love for programming! From my early days tinkering with code, I've delved into web dev, mobile apps, and AI. Sharing insights and tutorials with the world is my joy, connecting me to a global community of like-minded tech enthusiasts. Python holds a special place in my heart, but I embrace all challenges. Constantly learning, I attend tech conferences, contribute to open-source projects, and engage in code review sessions. My ultimate goal is to inspire the next generation of developers and contribute positively to the ever-evolving tech landscape. Let's code together!