Sheorey Digital Systems .NET Developer interview questions

Round 1: Interview : Focuses on Agile methodology, basic OOPS concepts. It is a plus if you know SOLID Principles and Design Patterns a bit. SQL: Difference between Primary and Unique key. Questions around Interface and access specifiers. Round 2: After few days, they give you a test to solve. Two sections: Section I: MCQ's on .net Framework, SQL, Winforms, REST Services. Section II: Programming question on string with a moderate difficulty level. Round 3: After few days they send you psychometric test. Round 4: HR Interview : Plain and smooth and they tell they'll contact you after approvals from senior management. Everything went well but, they did not give any offer letter. Everytime you contact them, they say approval is pending.