How to point out to a method in project to be executed inside a class library component

Question

In the past I had quite some reusable code in my project which I would like to put inside a custom class library project so other projects can reuse it. There is only just one piece of code which needs configuration in code which is project dependent.

How can I inject a method to be executed in my project inside a method of the class library? I was thinking about using a delegate but am open for suggestions. If you have some code, I am not that great with delegates, please post as well.

Answer 1

You're looking for different ways to achieve IOC/Dependency Injection. A common way is to take a parameter which implements:

interface IDoSomething
{
   void DoSomething(string myParam);
}

class MyLibrary
{
    public void DoLibraryStuff(IDoSomething iDoSomething, string extraParam)
    { iDoSomething.DoSomething("info");... }
}

If you'd like to use delegates you could use:

class MyLibrary
{
    public void DoLibraryStuff(Action<string> doSomething, string extraParam)
    { doSomething("info");... }
}

Usage:

new MyLibrary().DoLibraryStuff(info => Console.WriteLine(info), "extraParam");