1. IT College 2016, Andres käver http://enos.itcollege.ee/~akaver/csharp
C# - DELEGATES
IT College 2016, Andres käver

2. C# - Delegates
A delegate is a type that defines a method signature, and can provide a reference to any method with a compatible signature.
You can invoke (or call) the method through the delegate.
Delegates are used to pass methods as arguments to other methods.

3. C# - Delegates Basic usage
public delegate void SampleDelegate(string str);
class SampleClassDelegate {
// Method that matches the SampleDelegate signature.
public static void SampleMethod(string message)
// Add code here. }
// Method that instantiates the delegate.
void SampleDelegate()
SampleDelegate sd = SampleMethod;
sd("Sample string");

4. C# - Delegates Declare delegate signature (new type)
delegate returntype DelegateMethod(arguments….)
Declare delegate variable, assign suitable method to it
DelegateMethod methodCall = SomeSuitableMehtod;
Use methodCall in your code
methodCall(parameters…)

5. C# - Func<…>, Action<…>
Func<parameterTypes0..32,TResult>
To simplify code, don’t declare explicit new delegate – use Func
Func<bool> methodCall = someMethodNoArguments;
Func<int,bool> methodCall = someMehtodWithIntParameter;
When method returns void, use Action<parameterTypes0..32>

6. C# - Delegates, Anonymous methods
You can use anonymous method with delegates
Func<bool> methodCall = delegate() { return someMethod(); };
Func<int, bool> methodCall = delegate(int x) { return someMethod(x); };

7. C# - delegates, lambda expression
You can assign lambda expression to Func
Func<bool> methodCall = () => SomeMehtod();
Func<int, bool> methodCall = (x) => SomeMethod(x);