ActionFilterAttribute

[AttributeUsage(validOn: AttributeTargets.Method)]
public class HeaderRequiredAttribute : ActionFilterAttribute
{
    private readonly string _headerName;

    public HeaderRequiredAttribute(string headerName) =>
        _headerName = headerName;

    public override void OnActionExecuting(ActionExecutingContext context)
    {
        var httpContext = context.HttpContext;
        var headerValue = httpContext.Request.Headers[_headerName].ToString();
        if (string.IsNullOrWhiteSpace(headerValue))
            throw new MissingRequiredHeaderException(_headerName);
    }
}

public interface IDependency {}

public class DependencyImplOne : IDependency {}
public class DependencyImplTwo : IDependency {}

builder.Services.AddKeyedSingleton<IDependency, DependencyImplOne>("one");
builder.Services.AddKeyedSingleton<IDependency, DependencyImplTwo>("two");

public class BarService : IBarService
{
    public BarService([FromKeyedServices("one")] IDependency dependency) // DependencyImplOne
    {
    }
}

public class BazService : IBazService
{
    public BazService([FromKeyedServices("two")] IDependency dependency) // DependencyImplTwo
    {
    }
}

public interface IContract
{
    void Foo();
}

public partial class MyPartialClass
{
    // ...
}

public partial class MyPartialClass : IContract
{
    public virtual void Foo()
    {
        throw new NotImplementedException();
    }
}

public partial class MyPartialClassDerived : MyPartialClass
{
    public override void Foo()
    {
        Console.WriteLine(this);
        base.Foo();
    }
}