Microsoft Certified Solutions Developer (MCSD) Certification Practice Test

How do you specify constraints on a generic type in C#?

1. Using the "Select" clause

2. Using the "Where" clause

3. Using the "Type" clause

4. Using the "Constraint" clause

The correct answer is: Using the "Where" clause

In C#, constraints on a generic type are specified using the "Where" clause. This clause allows developers to restrict the types that can be used as arguments for a generic type parameter by applying specific constraints. For instance, you might require that a type parameter implements a particular interface, be a certain base class, or have a parameterless constructor. Here's an example of the syntax: ```csharp public class MyGenericClass<T> where T : IMyInterface { // Class implementation } ``` In this example, the "where T : IMyInterface" constraint specifies that the generic type parameter T must implement the IMyInterface interface. This ensures that any type used in place of T will have the members defined in that interface, enhancing type safety and usability within the class. The other options do not accurately describe the mechanism for imposing constraints on generic types. The "Select" clause, for instance, is related to LINQ queries and not applicable in this context. Similarly, the "Type" clause and "Constraint" clause are not valid terminologies in C# for specifying generic constraints. Thus, the "Where" clause is the correct and specific method to achieve this in C#.