Why is Autofac injecting null into my constructor?

Question

I am having issues with my DI in a C# project. When I run my test I am getting an error that says Object reference is not set to an instant of an Object. It is failing on the var retryPolicy = _retryPolicyHelper.GetRetryPolicy<>(); call and I'm not sure why. I thought the DI with the constructor handles the instantiation of the object.

internal read only IRetryPolicyHelper _retryPolicyHelper;
internal read only ILogger _logger;
public Constructor(IRetryPolicyHelper retryPolicyHelper, ILogger logger;)
{
 _retryPolicyHelper = retryPolicyHelper;
 _logger = logger;
}

public async Task SomeName(){
``var retryPolicy = _retryPolicyHelper.GetRetryPolicy<Some Return Type>();
}

Do you have code for where you register your components? If this is all you have, you are missing that part. — LarsTech, Jun 24 '22 at 22:38
I think an exception was thrown on the IRetryPolicyHelper implementation, please show your RetryPolicyHelper class — Saber Motamedi, Jun 25 '22 at 12:26
I was not registering them, that was the issue thanks so much. — Warfujjii, Jun 25 '22 at 15:31
Duplicate? https://stackoverflow.com/questions/4660142/what-is-a-nullreferenceexception-and-how-do-i-fix-it — Steven, Jun 25 '22 at 20:07
If you think this is not a duplicate, please provide a [Minimal, Reproducible Example](https://stackoverflow.com/help/minimal-reproducible-example) (MRE). Tip: a MRE is, at the very least, code that compiles. — Steven, Jun 25 '22 at 20:08

score 0 · Answer 1 · answered Jun 25 '22 at 20:52

0

Did you missed registration?

var builder = new ContainerBuilder();
builder.RegisterType<RetryPolicyHelper>().As<IRetryPolicyHelper>();

answered Jun 25 '22 at 20:52

Rui Ribeiro

17
3

Why is Autofac injecting null into my constructor?

1 Answers1