Microsoft Certified Solutions Developer (MCSD) Certification Practice Test

What is an ExpandoObject in C#?

1. An object that can only be changed at compile time

2. An object that can have members added or deleted at runtime

3. A static class for data manipulation

4. An interface for dynamic types

The correct answer is: An object that can have members added or deleted at runtime

An ExpandoObject in C# is designed to be a flexible data structure that allows you to dynamically add or delete members (properties, methods, and events) at runtime. This feature is particularly useful in scenarios where the schema of the data is not known at compile time, such as when working with JSON or XML data, or when integrating with dynamic data sources. The capability to modify an ExpandoObject at runtime means that it can adapt to various requirements as the program executes. This could involve adding new properties to capture additional information or removing properties that are no longer needed. The incorrect options describe characteristics that do not align with the functionality of an ExpandoObject. For instance, an ExpandoObject is not limited to compile-time modifications, nor is it a static class or an interface; it is a concrete implementation that supports dynamic behavior intrinsic to its design. This makes it a powerful tool for developers needing a flexible object model in C#.