Question

I want to create a function that recieve one parameter:
1. delegate that get any MyObj instance and returns a key (like OrderBy method).

So I can do the following:

function IQueryable<Worker> doSomething(Func<Worker, TKey> getter) {
    Workers.Where(x=>getter(x)==9);
}

This method should work with the entity framework. TKey is not defind. How can I do it?

Answer 1

If you want to compare it to a specific type, like an integer, just use that type in the signature:

public IQueryable<Worker> doSomething(Func<Worker, int> getter) {
  Workers.Where(x => getter(x) == 9);
}

Otherwise you would have to include it as a generic type and provide a value of that type for the comparison:

public IQueryable<Worker> doSomething<TKey>(Func<Worker, TKey> getter, TKey value) {
  Workers.Where(x => getter(x).Equals(value));
}