List Of 10 MVVM Interview Questions (With Sample Answers)

Updated 27 September 2022

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Model-view-viewmodel (MVVM) is an architectural structure that programmers use to build web applications. When you interview for a role that might require your proficiency in MVVM, the hiring manager may ask you questions to understand your skills and experience better. When preparing for your interview, reading some popular questions and answers can help you prepare and impress a hiring manager. In this article, we go over some MVVM interview questions and sample answers and review a list of tips to help you in your interview process.

MVVM Interview Questions And Sample Answers

If you are looking for a job as a web programmer, reviewing MVVM interview questions can help you create effective answers during an interview. Here are some questions with sample answers that you may get asked in one of these interviews:

1. What is MVVM?

Angular is a structure programmers use to develop apps. The interviewer may start the interview with this question before easing into more detailed questions. Answer this question by briefly explaining what MVVM is and talking about some of its benefits.

Example: "MVVM is a software design pattern used by programmers to develop user interfaces for web applications. It makes it easy to maintain and develop complicated user interfaces. The viewmodel in MVVM is efficient in managing data and business logic, while it displays the data through the view. It separates the concerns of the application, making web development easier."

2. Tell us about data binding in MVVM.

Data binding is an essential aspect of programming. The way you talk about this concept to your interviewer can show your ability to explain complex coding concepts to your colleagues who work outside your department.

Example: "Data binding in MVVM is used to connect the data source with the data target. A data target can be a text box or a combo box. While a data source can be any common language runtime (CLR) object. With the help of data binding, all data gets synchronised. This means that any changes in the source get reflected in the data target. Similarly, any changes in the data target are identifiable in the data source. This eliminates the requirement for manual updates and makes coding easier."

3. How is MVVM different from model view controller (MVC) and other design patterns?

MVVM separates the user interface and data, which reduces the amount of coding required. By asking this question, the hiring manager wants to know if you are aware of different design patterns used by programmers. Answer this question by comparing MVVM to MVC and discuss which one you prefer when developing applications.

Example: "The primary difference between other design patterns and MVVM is that it separates the user interface from the data. This forms a database which is easier to test and modify. It also uses data binding, which reflects any changes in the data source when the model changes. I prefer MVVM, as it simplifies the coding process."

4. Do you think there are any disadvantages to using MVVM?

There are a few disadvantages to using MVVM if the UI is too simple or too complex. The hiring manager may want to know if you can choose the right design pattern for a project instead of using the same one every time. Based on your experience of using MVVM, talk about some flaws in the MVVM design structure.

Example: "MVVM is a useful design structure, and I have used it several times to develop applications. In my experience, I think it may not always be necessary for apps with a simple user interface. If the user interface is too complex, it can get difficult to design the view model. The more complex the data binding is in MVVM, the more difficult it becomes to debug the program."

5. Does every separate XAML file containing child content require to be an MVVM view?

You do not require a separate viewmodel for every child content you store in an extensible application markup language (XAML) file. Elaborate about this in more detail in your answer. The interviewer can assess if you understand the technical details of the framework.

Example: "If the chunk of data provides the structure to render something to the screen and does not support any manipulation by the user, then that content does not require a separate XAML file. It may not require a separate viewmodel, but it can be a chunk XAML that renders based on properties shown by the parent viewmodel."

6. What are the advantages of MVVM?

The hiring manager may ask you questions about the specific features and advantages of the MVVM design structure. Try to explain your answer simply and precisely. Elaborate and share examples if the interviewer asks for more details.

Example: "MVVM design structure is the modern version of the Model-View-Controller (MVC) pattern, so its primary motive remains to provide a clear separation between the view and model. This helps programmers work more efficiently. In simple terms, when the model requires a change, we can change it easily without making changes to the view."

7. What is a data template?

A template describes the overall look and visual appearance of the control. By asking such technical questions, the hiring manager tries to assess if your knowledge of MVVM can enable you to perform the daily duties as an employee after getting hired. Try to keep your answer brief and simple.

Example: "Every control has a default template associated with it. This template determines the visual appearance of that control. We can easily customise these templates if we wish to alter the visual behaviour and visual appearance of a control. In addition, we can also achieve connectivity between the logic and template by the use of data binding."

8. What are some popular MVVM frameworks?

There are three popular MVVM frameworks. Name them in your answer. It can demonstrate your knowledge of the MVVM framework to the employer.

Example: "Some popular MVVM frameworks are Prism, MVVM Light and Caliburn Micro."

9. What do you mean by reactive programming?

Reactive programming is a design paradigm that depends on asynchronous programming logic to manage real-time updates to static content. Explain this concept briefly in your answer to show your proficiency in the subject.

Example: "Reactive programming is a model that is concerned with data streams and propagation of change. It means that every time a piece of data changes, all observers of that data receive a notification automatically. This method is more efficient compared to the traditional way of manually monitoring changes in data and then updating the observers accordingly."

10. Can you tell us about observers and observables in reactive programming?

In reactive programming, observables may stream and consume data. The interviewer may want to test your ability to explain these terms in a comprehensible way so you can later guide your team on the same or similar subjects.

Example: "In reactive programming, observers are objects that consume data while observables are objects that emit a stream of data. Observers can consume data to update the user interface. You can use observables to emit data from a viewmodel to a view."

Interview Preparation Tips

Here are some interview tips you may find useful to increase your chances of success:

Research the company. Conduct research on the company and identify the areas where you can contribute effectively. This can be useful to convey suitability for the role.
Wear formal attire. Try to wear formal attire in which you are comfortable and confident. This can help you focus more on conversing with the interviewers.
Implement the STAR method. It can be helpful if you apply the STAR method, which includes situation, task, action and results, to answer specific scenario-based or efficiency-based queries to show your approach and how you maintain your efficiency levels.

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