Microsoft Certified Solutions Developer (MCSD) Certification Practice Test

How would you implement a WeakReference in C#?

1. WeakReference myRef = new WeakReference(myObject);

2. WeakReference myRef = WeakReference(new myObject());

3. WeakReference myRef = new WeakReference(this);

4. WeakReference myRef = CreateWeakReference(myObject);

The correct answer is: WeakReference myRef = new WeakReference(myObject);

The implementation of a WeakReference in C# involves using the constructor provided by the WeakReference class, which allows you to create a reference to an object without preventing it from being garbage collected. The correct choice demonstrates this properly: by creating a new instance of WeakReference and passing in the object you want to reference, you establish a weak link to that object. Using the code `WeakReference myRef = new WeakReference(myObject);` correctly instantiates a weak reference. When the object referenced by myObject has no strong references to it, the garbage collector can reclaim that memory, allowing for better memory management in applications. This use case is particularly beneficial in managing large objects or resources where you want to allow them to be collected if they are not needed anymore, while still having the ability to access them if they are available. The other options contain incorrect syntax or conceptual misunderstandings about how to instantiate a WeakReference. For instance, calling WeakReference as if it were a method or trying to directly instantiate a new WeakReference without the proper constructor would not produce valid code. Understanding the purpose and proper syntax for creating weak references is crucial for managing memory effectively in C#.