Wilco Source Senior ASP.NET Developer Interview Questions and Answers

To improve web application, I use tools like profiling, caching, compression, and optimization.

• I use profiling tools like MiniProfiler and Glimpse to identify performance bottlenecks.

• I implement caching using tools like Redis and Memcached to reduce database queries and improve response time.

• I use compression techniques like Gzip and Brotli to reduce the size of files sent over the network.

• I optimize images, scripts, a...read more

MVC is a design pattern used in web development. MVC is better than ASP.NET web forms for complex applications.

• MVC separates application into Model, View, and Controller

• MVC provides better control over HTML, CSS, and JavaScript

• MVC is better for complex applications with multiple developers

• ASP.NET web forms are better for simple applications with rapid development

• MVC is more testable than ASP.NET web forms

Razor engine is a markup syntax used to create dynamic web pages in ASP.NET. It is faster than typical ASP pages.

• Razor engine is a server-side markup syntax used to create dynamic web pages in ASP.NET

• It allows developers to embed server-side code into HTML content

• Razor pages are faster than typical ASP pages because they are compiled into C# code before being executed

• Razor pages have a cleaner syntax and are easier to ...read more

LINQ equivalent of LEFT JOIN is DefaultIfEmpty()

• Use DefaultIfEmpty() method to perform LEFT JOIN in LINQ

• Use into keyword to create a temporary variable for the join

• Example: var result = from a in tableA

• join b in tableB on a.Id equals b.Id into temp

• from b in temp.DefaultIfEmpty()

• select new { a.Id, b.Name }

Code First and DB First are two approaches to create Entity Framework models.

• Code First: Create classes first and generate database schema from them.

• DB First: Create database schema first and generate classes from it.

• Code First is more flexible and allows for easier version control.

• DB First is useful when working with legacy databases.

• Both approaches use Entity Framework to map database tables to classes.

Scaffold tool is used to create models in Entity Framework

• Scaffold-DbContext command in Package Manager Console

• Visual Studio's Add New Item > ADO.NET Entity Data Model

• Entity Data Model Wizard in Visual Studio

Entity Framework is used to create class objects from DB First

• Entity Framework is a popular ORM tool used in .NET development

• It can generate classes based on an existing database schema

• This process is known as Database First approach

• The generated classes are called Entity Classes

• Entity Framework also supports Code First and Model First approaches

Web API is a framework for building HTTP services that can be accessed from various clients.

• Web API is built on top of ASP.NET framework.

• It supports HTTP verbs like GET, POST, PUT, DELETE, etc.

• It can return data in various formats like JSON, XML, etc.

• It can be used to build RESTful services.

• It can be consumed by various clients like web browsers, mobile apps, etc.

SOLID is a set of principles for object-oriented programming that aims to make software more maintainable, scalable, and flexible.

• S - Single Responsibility Principle: A class should have only one reason to change.

• O - Open/Closed Principle: Software entities should be open for extension but closed for modification.

• L - Liskov Substitution Principle: Subtypes must be substitutable for their base types.

• I - Interface Segreg...read more

Agile process is an iterative approach to software development that emphasizes flexibility and customer satisfaction.

• Agile process involves breaking down the project into smaller, manageable chunks called sprints.

• Each sprint typically lasts 1-4 weeks and results in a working product increment.

• The team works closely with the customer to ensure that the product meets their needs and expectations.

• Agile process values indi...read more

Scaffolding is a code generation technique used in MVC to create basic CRUD operations for a model.

• Scaffolding generates boilerplate code for Create, Read, Update, and Delete operations

• It saves time and effort by generating code for repetitive tasks

• Developers can customize the generated code to fit their specific needs

SSRS stands for SQL Server Reporting Services, a server-based reporting platform that allows creating and managing reports.

• SSRS is a part of Microsoft SQL Server.

• It provides a set of tools to create, deploy, and manage reports.

• Reports can be created using various data sources like SQL Server, Oracle, Excel, etc.

• Reports can be exported to various formats like PDF, Excel, Word, etc.

• SSRS also provides a web-based interfac...read more

MVC Filters are used to implement cross-cutting concerns in ASP.NET MVC applications.

• Authorization Filters

• Action Filters

• Result Filters

• Exception Filters

Authorization filter checks if the user has access to the requested resource after a page re-direct.

• Authorization filter is executed after the page re-direct is completed.

• It checks if the user has the necessary permissions to access the requested resource.

• If the user is not authorized, the filter will redirect the user to the login page or display an error message.

• Authorization filter can be applied globally or on spec...read more

MVC routes are used to map URLs to controller actions. To change a particular action's route, we can use the Route attribute.

• MVC routes are defined in the RouteConfig.cs file in the App_Start folder.

• To change a particular action's route, we can use the Route attribute above the action method.

• For example, [Route('Employee')], will change the URL from /EmployeeDetails to /Employee.

• We can also specify parameters in the ro...read more

Secure data in SQL server using encryption, access control, and regular backups.

• Encrypt sensitive data using TDE or column-level encryption

• Implement access control using roles and permissions

• Regularly backup data to prevent loss or corruption

• Use strong passwords and limit access to the server

• Monitor for suspicious activity and implement auditing

The application can choose the respective database based on the user's location or other criteria.

• Use a load balancer to route traffic to the appropriate database server based on user location

• Implement a database sharding strategy to distribute data across multiple databases

• Use a master-slave replication setup to replicate data across multiple databases

• Implement a database routing layer that can dynamically route reque...read more

Database concurrency refers to the ability of multiple users to access and modify the same data simultaneously.

• Concurrency control mechanisms ensure that data remains consistent and accurate.

• Locking, optimistic concurrency control, and transaction isolation levels are common techniques used to manage concurrency.

• Concurrency issues can lead to data inconsistencies and conflicts, such as lost updates and dirty reads.

Choose Code First for flexibility, DB First for legacy systems.

• Code First allows for more flexibility in designing the database schema

• DB First is useful for working with legacy systems or pre-existing databases

• Consider the project requirements and team expertise when making a decision

WebApi authentication can be done using various methods such as JWT, OAuth, Basic Authentication, etc.

• JWT authentication involves generating a token that is sent with each request

• OAuth authentication involves obtaining an access token from a third-party provider

• Basic Authentication involves sending a username and password with each request

• Other methods include API keys, client certificates, and custom authentication sc...read more

Triggers are database objects that execute automatically in response to certain events.

• Triggers are used to maintain the integrity of data in a database.

• There are two types of triggers: DML triggers and DDL triggers.

• DML triggers are fired in response to DML (Data Manipulation Language) events like INSERT, UPDATE, and DELETE.

• DDL triggers are fired in response to DDL (Data Definition Language) events like CREATE, ALTER, ...read more

Triggers are used to automatically execute a set of actions when a specific event occurs in a database.

• Triggers can be used to enforce business rules and data integrity.

• They can be used to audit changes made to the database.

• Triggers can also be used to replicate data across multiple tables or databases.

• Examples of trigger events include INSERT, UPDATE, and DELETE operations on a table.

Magic Tables are temporary tables created by SQL Server during DML operations.

• Magic Tables are used to access the data before and after a DML operation.

• They are created automatically by SQL Server and cannot be accessed directly.

• They are useful for auditing and logging changes to a table.

• The inserted and deleted tables are examples of Magic Tables.

Temporary tables are tables that exist temporarily in the database and are used to store intermediate results.

• Temporary tables are created using the CREATE TABLE statement with the # symbol before the table name.

• They are useful for storing intermediate results during complex queries or procedures.

• Temporary tables are automatically dropped when the session that created them ends or when the connection is closed.

• They can...read more

CTE is a temporary result set that can be referenced within a SELECT, INSERT, UPDATE, or DELETE statement.

• CTE is defined using the WITH keyword followed by a name and a SELECT statement.

• It can be used to simplify complex queries and improve performance.

• CTE can be recursive, allowing a query to reference itself.

• Example: WITH sales AS (SELECT * FROM orders WHERE status = 'completed') SELECT * FROM sales;

• Example: WITH rec...read more

Unit testing is a software testing technique to test individual units or components of a software application.

• Unit testing is done to ensure that each unit/component of the software application is working as expected.

• It helps in identifying and fixing bugs early in the development cycle.

• Unit testing is usually automated and can be run frequently to ensure that changes made to the code do not break existing functionalit...read more

I have used both GIT and TFS for source control.

• I have used GIT for personal projects and TFS for enterprise-level projects.

• I am familiar with branching, merging, and pull requests in both GIT and TFS.

• I have experience with using GIT and TFS in conjunction with continuous integration and deployment tools.

• I have also used tools like SourceTree and Visual Studio Team Explorer for managing source control.

TFS is a centralized version control system while GIT is a distributed version control system.

• TFS is tightly integrated with Microsoft products while GIT is more flexible and can be used with any platform.

• TFS has a more complex branching and merging system while GIT has a simpler and more efficient system.

• TFS has a centralized repository while GIT has a distributed repository.

• TFS has a more comprehensive set of feature...read more

Yes, I have experience with Token based authorization.

• I have implemented token based authentication using JWT (JSON Web Tokens) in several projects.

• I have used OAuth 2.0 to generate access tokens for API authentication.

• I have integrated token based authorization with ASP.NET Identity for user authentication and authorization.

• I have also worked with refresh tokens to extend the validity of access tokens.

• I am familiar wi...read more