Passing a Function (with parameters) as a parameter?

Question

I want to create a generic to which I can pass a function as a parameter, however this function may include parameters itself so...

int foo = GetCachedValue("LastFoo", methodToGetFoo) 

Such that:

protected int methodToGetFoo(DateTime today) { return 2; // example only } 

Essentially I want to have a method that will check the cache for a value, otherwise will generate the value based on the passed in method.

Thoughts?

Answer 1

It sounds like you want a Func<T>:

T GetCachedValue<T>(string key, Func<T> method) {      T value;      if(!cache.TryGetValue(key, out value)) {          value = method();          cache[key] = value;      }      return value; } 

The caller can then wrap this in many ways; for simple functions:

int i = GetCachedValue("Foo", GetNextValue); ... int GetNextValue() {...} 

or where arguments are involved, a closure:

var bar = ... int i = GetCachedValue("Foo", () => GetNextValue(bar)); 

Answer 2

Use System.Action and a lambda expression (anonymous method). For example:

public void myMethod(int integer) {          // Do something }  public void passFunction(System.Action methodWithParameters) {     // Invoke     methodWithParameters(); }  // ...  // Pass anonymous method using lambda expression passFunction(() => myMethod(1234));