C# .NET interview questions

What is Shared Assembly ?

Answer:

Shared Assemblies contain Common Libraries which are intended to be used by multiple applications. While making shared assemblies, name collisions and overwriting existing assemblies need to be taken care. Name Collisions can be taken care by strong name. Global assembly cache can be used to avoid assembly overwriting.

What is a Private Assembly ?

Answer:

Private Assemblies are intended to be used by the program for which it is made for. Reason behind this is that, the application will only load private assemblies that are located in the same folder or in the sub folder of the main executable.

What are the different types of Assembly ?

Answer:

The two types of Assemblies are Shared and Private.

What is Assembly Manifest ?

Answer:

Part of the assembly which contains assembly meta data that describes the assembly itself is known as manifest. Assembly manifest contains Assembly Name, Version Number, Culture, Strong name, List of files inside the assembly and Reference information.

What is an Assembly ?

Answer:

Assemblies are self-describing logical unit which consists of one or more files targeted at dot net. An assembly can be stored across single file such as a single DLL or EXE that includes metadata, or it can be stored in multiple files. For example, resource files like meta data, DLL's, and an EXE. Assemblies support versioning.

What is a Managed Code ?

Answer:

Managed code is code that can be executed and managed by .NET Framework Common Language Runtime. All codes based on the intermediate language(EL) executes as managed code.

How to invoke garbage collector programmatically ?

Answser:

To call garbage collector from a program, use code “ GC.Collect(); “

What is Garbage Collector ?

Answer:

Garbage Collector is used in dot net Framework for memory management. While running an application, applications make a request for memory for its internal use. Framework allocates memory from the heap. Once the process is completed, allocated memory needs to be reclaimed for future use. The process of reclaiming unused memory is taken care by the Garbage Collector.

What is Common Language Specification (CLS) ?

Answer:

Common Language Specification (CLS) is used for Language Interoperability in tandem with CTS to ensure the interoperability of the languages. CLS defines a set of minimum standards that all compilers targeting dot net must support. For example, VB.Net is not case sensitive. So attribute “EmployeeName” and “employeename” is considered same. But C# is case sensitive. So for language interoperability, C# doesn't allow two variables which differ only in case.

What is Common Type System (CTS) ?

Answer:

.Net uses Common Type System (CTS) for Language Interoperability. CTS defines the predefined data types that are available in IL, so that all languages that target the .NET framework will produce the compiled code that is ultimately based on these types. CTS ensures that a data type defined in a VB.net will be understood by C#. For example, VB.Net uses “Integer” to define the data type Integer. C# uses  “int” to define the data type Integer. When VB.Net code is compiled, it will convert the Integer to Int32. Since C# refers Int to Int32, VB.Net code will be understood by C#.

What is Common Language Runtime (CLR) ?

Answer:

Common Language Runtime or CLR is the run-time execution environment of .Net Framework. Converting MS-IL into platform or OS specific code is done by the CLR. Currently, .Net programs will run only on windows.

What is MS-IL (Microsoft Intermediate Language) ?

Answer:

When a program is complied in .Net, the source code will be converted into an intermediate language called Microsoft Intermediate Language (MS-IL). This is done by Just-In time Compiler (JIT). The dot net framework is built in such a way that the code is Just-In time complied, which means that it get complied when it is called rather than compiling entire code at the start up. A portion of the code will get complied only once and it will exist till the application exit. This will have a significant improvement in performance since the entire section of the code won't get executed in most cases.

What is .Net Framework ?

Answer:

The .NET framework is a programming framework from Microsoft. Developers can use .Net Framework to develop applications, install and run the application on Windows operating systems.

What are the advantages of .Net?

Answer:

• Good Design
• Object-Oriented Programming – Using C# and .NET which are based on object-oriented Concepts.
• Language Independence – All the languages which are supported by .Net (VB.NET, C#, J#, and managed C++) are compiled into common Intermediate Language (IL). So IL makes sure that languages are interoperable.
• Efficient Data Access – ADO.NET provides fast and efficient way to access RDBMS, file system etc.
• Code Sharing – To share code between applications, a new concept called assembly is introduced. Assemblies supports versioning.
• Improved Security
• Support Dynamic Web Pages – Using ASP.NET
• Support for Web Services