Microsoft Certified Solutions Developer (MCSD) Certification Practice Test

What is Boxing in C#?

1. Converting a reference type to a value type

2. Storing a value type in an object

3. Converting a string to an integer

4. Creating an object from a class

The correct answer is: Storing a value type in an object

Boxing in C# refers specifically to the process of storing a value type in an object. Value types, such as integers and floating-point numbers, are stored directly on the stack, whereas reference types, which include classes and arrays, are stored in the heap. When a value type is boxed, it is encapsulated within a reference type, allowing it to be treated as an object. This is important because it enables value types to be used in contexts that require reference types, such as in collections or when passing values to methods that expect an object parameter. When a value type is boxed, a new object is allocated on the heap, and a copy of the value is stored in that object. This means that any changes made to the boxed object do not affect the original value type, as they are two distinct entities in memory. The other options do not accurately define boxing. Converting a reference type to a value type describes unboxing, which is the reverse process—extracting the value type from the boxed object. Converting a string to an integer is a completely different operation, known as parsing. Creating an object from a class is just standard object instantiation and is not related to boxing at all.