FluentValidation | A popular NET validation library for building strongly-typed validation rules | Validation library

(Found an answer shortly after posting question)

We can achieve the validation using the derived model and a specific RuleForEach syntax:

One possible solution:

I am slightly modified your code for my better understanding.

You have a model with an optional value. Within a user-defined method you validate that this value is defined. The compiler can't determine this behaviour and thous the warning.

To help the compiler you could use the null-forgiving operator like this:

Below is the best set of conclusions that I could derive from all the comments on the question.

Injection constructors should be simple, and in the context of Fluent Validation, the MustAsync method should help to simplify asynchronous validation.

While I can use JoinableTaskFactory, I should not be getting this warning, because the problem it is trying to solve is not applicable to .NET Core.

Below is the description from the documentation for JoinableTaskFactory. It applies to situations where joining threads to the main thread could cause deadlocks.

A factory for starting asynchronous tasks that can mitigate deadlocks when the tasks require the Main thread of an application and the Main thread may itself be blocking on the completion of a task.

Thus, one can safely ignore the warning in the cases where it is simply not possible to rewrite the code. (Note the use of Task.Run(), which is the recommended way to launch a compute-bound task as of .NET Framework 4.5.)

The answer was (unsurprisingly) that I needed to wrap the calls with other calls rather than use the MediatR pipeline. So I created an IDispatcher interface.

In Program.cs...

If you are using your controller something like [HttpGet("example/{param1:string}/{param2:Guid}")] then just remove :string. change it to [HttpGet("example/{param1}/{param2:Guid}")].

And for your cors issue:-

Use below code:-

Not enough reputation for a comment, have you tried following this article? Serilog log to SQL.

You haven't added the logging table but I'm going to assume that you followed the Sink and it resembles or is a match to this one?

with fluent validation it is absolutely possible to create validator for simple types as well such as int and string.

You just have to write a custom validator for your object. In case you only need a simple string or int than create an object with that property for which you can write the validation.

Take a look at this one: https://codewithmukesh.com/blog/fluent-validation-aspnet-core/