Technical interview questions and answers are critical when preparing for an AJAX Interview because companies want to evaluate your understanding of asynchronous communication, XMLHttpRequest, JSON handling, DOM manipulation, and interactive web applications. AJAX is considered a core concept in modern web development, and many companies include it as part of their technical rounds for frontend and full-stack developer roles. Organizations like TCS, Infosys, Wipro, Cognizant, and Capgemini frequently ask AJAX-related questions to check whether candidates can build dynamic, responsive, and efficient web pages. This guide includes commonly asked AJAX interview questions with clear explanations to help freshers and job seekers strengthen their web development fundamentals. These questions will improve your preparation for placement interviews, coding rounds, and real-time project discussions.
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161. If a base class has a number of overloaded constructors, and an inheriting class has a number of overloaded constructors; can you enforce a call from an inherited constructor to a specific base constructor?
Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.
162. Whats a delegate?
A delegate object encapsulates a reference to a method.
163. Whats a multicast delegate?
A delegate that has multiple handlers assigned to it. Each assigned handler (method) is called.
164. Why are there five tracing levels in System.Diagnostics.TraceSwitcher?
The tracing dumps can be quite verbose. For applications that are constantly running you run the risk of overloading the machine and the hard drive. Five levels range from None to Verbose, allowing you to fine-tune the tracing activities.
165. What are three test cases you should go through in unit testing?
1. Positive test cases (correct data, correct output).
2. Negative test cases (broken or missing data, proper handling).
3. Exception test cases (exceptions are thrown and caught properly).
166. Can you change the value of a variable while debugging a C# application?
Yes. If you are debugging via Visual Studio.NET, just go to Immediate window.
167. What is the role of the DataReader class in ADO.NET connections?
It returns a read-only, forward-only rowset from the data source. A DataReader provides fast access when a forward-only sequential read is needed.What are advantages and disadvantages of Microsoft-provided data provider classes in ADO.NET?
SQLServer.NET data provider is high-speed and robust, but requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle, DB2, Microsoft Access and Informix. OLE-DB.NET is a .NET layer on top of the O
168. What is the wildcard character in SQL?
Lets say you want to query database with LIKE for all employees whose name starts with La. The wildcard character is %, the proper query with LIKE would involve ‘La%.
169. What connections does Microsoft SQL Server support?
Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and password).
170. Between Windows Authentication and SQL Server Authentication, which one is trusted and which one is untrusted?
Windows Authentication is trusted because the username and password are checked with the Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only verifier participating in the transaction.