Question

I was wondering how to go about writing a custom attribute which can access both the input and output parameters of a function.

Below is an example of what I wish to achieve

[CustomAttribute("Creating Foo")]
public Foo CreateFoo(Foo newFoo)
{
    //do logic
    return newlyCreatedFoo;
}

From this, the CustomAttribute will create an entry in a DB with the “Creating Foo” tag, which is easy enough to do, but I want to be able to access both newFoo and newlyCreatedFoo as well. Is this possible?

Answer 1

I am afraid that this is not possible with custom attributes.

This could be achieved with post compilation processing. Tools like PostSharp would allow you to achieve this functionality.