Question

I have some code (not writted by me) that I don’t understand:

private Func<ControllerContext, string> ThemeSelector { get; set; }

So this is not a type, this is Func < T, string > and I don’t know how this kind of thing is named but I am unable to find some explanations on Google. Does someone can gives me some explanations of giving me a link to explain?

Thanks.

Answer 1

Func<ControllerContext, string> is a specific type of the generic Func<T,K>.
You need to learn about generics first before you can fully understand that.

Therefore ThemeSelector is just a property of that type, which has setter and getter.

The Func type is a delegate type, which represents a function that takes one parameter of type T and returns an instance of type K.

This means that you can assign any such function to the property. E.g.:

private string MyFunction(ControllerContext context) {
    return "Hello world!";
}

...

ThemeSelector = MyFunction;

Console.WriteLine(ThemeSelector(null));

will print “Hello world!” in the console.