Event Driven Handouts 1 & 2

What is a delegate in C#?

• a) A class in .NET used to encapsulate methods.

• b) A reference type that holds a method reference.

• c) A feature to manage events automatically.

• d) An object for storing string values.

Answer explanation

What is required for a method to be referenced by a delegate?

• a) The method must be public.

• b) The method's signature must match the delegate's signature.

• c) The method must be static.

• d) The method must not take any parameters.

What is the correct syntax for declaring a delegate?

• a) delegate void DelegateName();
  

• b) public event DelegateName();
  

• c) public delegate DelegateName();
  

• • d) public delegate int DelegateName(int x, int y);

How do you invoke a delegate in C#?

• a) DelegateName.Invoke();
  

• b) delegateInstance(10, 20);
  

• c) delegate.Invoke(10, 20);
  

• • d) delegateInstance();

True or False: A delegate can reference multiple methods at once.

• True

• False

In the example below, which delegate is valid for referencing the method CalculateSum(int x, int y) that returns an integer?

• a) public delegate void CalculateSumDelegate(int x);
  

• b) public delegate int CalculateSumDelegate();
  

• c) public delegate int CalculateSumDelegate(int x, int y);
  

• • d) public delegate string CalculateSumDelegate(int x, int y);

Which statement correctly instantiates a delegate for the GetSum method?

• a) CalculateDelegate sumDelegate = new CalculateDelegate(GetSum);
  

• b) CalculateDelegate sumDelegate += GetSum;
  

• c) delegate sumDelegate = GetSum;
  

• 6. d) new CalculateDelegate sumDelegate(GetSum);

What is a generic delegate in C#?

• a) A delegate that does not require specifying a type.
  

• b) A delegate that automatically handles all events.
  

• c) A delegate that references methods with any return type and parameter types.
  

• • d) A delegate used only for string methods.

Which of the following is a correctly declared generic delegate?

• a) public delegate T GenericDelegate<T>(T value);
  

• b) delegate string GenericDelegate<string>(string value);
  

• c) public delegate GenericDelegate<T>(T value);
  

• • d) generic delegate void GenericDelegate();

8. True or False: A generic delegate can point to a method that takes different data types as long as the method's parameters match the delegate signature.

• True

• False