C# - Delegates Question and Answer
C# - Delegates Question and Answer
1. Which of the following statements is incorrect about delegate?
- Delegates are reference types.
- Delegates are object oriented.
- Delegates are type-safe.
- Delegates serve the same purpose as function pointers in C and pointers to member function operators in C++.
2. In which of the following areas are delegates commonly used?
Remoting
Serialization
File Input/Output
Multithreading
Event handling
Remoting
Serialization
File Input/Output
Multithreading
Event handling
- 1 and 2 only
- 1 and 5 only
- 1, 2 and 3 only
- 4 and 5 only
3. Which of the following is the necessary condition for implementing delegates?
- Class declaration
- Inheritance
- Run-time Polymorphism
- Exceptions
4. Which of the following statements are correct about the delegate declaration given below?
delegate void del(int i);
On declaring the delegate a class called del will get created.
The signature of del need not be same as the signature of the method that we intend to call using it.
The del class will be derived from the MulticastDelegate class.
The method that can be called using del should not be a static method.
The del class will contain a one-argument constructor and an lnvoke() method.
delegate void del(int i);
On declaring the delegate a class called del will get created.
The signature of del need not be same as the signature of the method that we intend to call using it.
The del class will be derived from the MulticastDelegate class.
The method that can be called using del should not be a static method.
The del class will contain a one-argument constructor and an lnvoke() method.
- 1, 2 and 3 only
- 1, 3 and 5 only
- 2 and 4 only
- 4 only
5. Which of the following statements are correct about a delegate?
Inheritance is a prerequisite for using delegates.
Delegates are type-safe.
Delegates provide wrappers for function pointers.
The declaration of a delegate must match the signature of the method that we intend to call using it.
Functions called using delegates are always late-bound.
Inheritance is a prerequisite for using delegates.
Delegates are type-safe.
Delegates provide wrappers for function pointers.
The declaration of a delegate must match the signature of the method that we intend to call using it.
Functions called using delegates are always late-bound.
- 1 and 2 only
- 1, 2 and 3 only
- 2, 3 and 4 only
- All of the above
6. Which of the following statements are correct about delegates?
Delegates are not type-safe.
Delegate is a user-defined type.
Only one method can be bound with one delegate object.
Delegates can be used to implement callback notification.
Delegates permit execution of a method on a secondary thread in an asynchronous manner.
Delegates are not type-safe.
Delegate is a user-defined type.
Only one method can be bound with one delegate object.
Delegates can be used to implement callback notification.
Delegates permit execution of a method on a secondary thread in an asynchronous manner.
- 1 and 2 only
- 1, 2 and 3 only
- 2, 4 and 5 only
- 4 and 5 only
7. Which of the following statements are correct about delegates?
- Delegates cannot be used to call a static method of a class.
- Delegates cannot be used to call procedures that receive variable number of arguments.
- If signatures of two methods are same they can be called through the same delegate object.
- Delegates cannot be used to call an instance function. Delegates cannot be used to call an instance subroutine.
8. Which of the following are the correct ways to declare a delegate for calling the function func() defined in the sample class given below?
class Sample
{
public int func(int i, Single j)
{
/* Add code here. */
}
}
class Sample
{
public int func(int i, Single j)
{
/* Add code here. */
}
}
- delegate d(int i, Single j);
- delegate void d(int, Single);
- delegate int d(int i, Single j);
- delegate void (int i, Single j);
9. Suppose on pushing a button an object is to be notified, but it is not known until runtime which object should be notified. Which of the following programming constructs should be used to implement this idea?
- Attribute
- Delegate
- Namespace
- Interface
10. Which of the following statements is incorrect about a delegate?
- A single delegate can invoke more than one method.
- Delegates can be shared.
- Delegate is a value type.
- Delegates are type-safe wrappers for function pointers