C# Interview Questions, Part 2
21. What’s the difference between an interface and abstract class? In the interface all methods must be abstract; in the abstract class some methods can be concrete. In the interface no accessibility modifiers are allowed, which is ok in abstract classes.
22. How can you overload a method? Different parameter data types, different number of parameters, different order of parameters.
23. If a base class has a bunch of overloaded constructors, and an inherited class has another bunch of overloaded constructors, can you enforce a call from an inherited constructor to an arbitrary 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.
24. What’s the difference between System.String and System.StringBuilder classes? System.String is immutable; System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.
25. What’s the advantage of using System.Text.StringBuilder over System.String? StringBuilder is more efficient in the cases, where a lot of manipulation is done to the text. Strings are immutable, so each time it’s being operated on, a new instance is created.
26. Can you store multiple data types in System.Array? No.
27. What’s the difference between the System.Array.CopyTo() and System.Array.Clone()? The first one performs a deep copy of the array, the second one is shallow.
28. How can you sort the elements of the array in descending order? By calling Sort() and then Reverse() methods.
29. What’s the .NET datatype that allows the retrieval of data by a unique key? HashTable.
30. What’s class SortedList underneath? A sorted HashTable.
31. Will finally block get executed if the exception had not occurred? Yes.
32. What’s the C# equivalent of C++ catch (…), which was a catch-all statement for any possible exception? A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}.
33. Can multiple catch blocks be executed? No, once the proper catch code fires off, the control is transferred to the finally block (if there are any), and then whatever follows the finally block.
34. Why is it a bad idea to throw your own exceptions? Well, if at that point you know that an error has occurred, then why not write the proper code to handle that error instead of passing a new Exception object to the catch block? Throwing your own exceptions signifies some design flaws in the project.
35. What’s a delegate? A delegate object encapsulates a reference to a method. In C++ they were referred to as function pointers.
36. What’s a multicast delegate? It’s a delegate that points to and eventually fires off several methods.
37. How’s the DLL Hell problem solved in .NET? Assembly versioning allows the application to specify not only the library it needs to run (which was available under Win32), but also the version of the assembly.
38. What are the ways to deploy an assembly? An MSI installer, a CAB archive, and XCOPY command.
39. What’s a satellite assembly? When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.
40. What namespaces are necessary to create a localized application? System.Globalization, System.Resources.
C# interview questions and answers
1. What’s the advantage of using System.Text.StringBuilder over System.String?
StringBuilder is more efficient in cases where a large amount of manipulation is done in the text. Strings are immutable, so it is increasingly being operated, a new instance is created.
2. Can you store multiple data types in System.Array?
No.
3. What’s the difference between the System.Array.CopyTo() and System.Array.Clone()?
The first three performs a deep copy of the array, the second three is shallow.
4. How can you sort the elements of the array in descending order?
By calling Sort() and then Reverse() methods.
5. What’s the C# equivalent of C++ catch (…), which was a catch-all statement for any possible exception?
A catch block that catches the exception of type Process.Exception. You can also omit the parameter information type in this case and write catch {}.
6. Why is it a bad idea to throw your own exceptions?
Well, if that point is known that an error has occurred, why not write the code of law to resolve this error, instead of passing a new Exception object to the catch block? Start your own exclusions means that some design flaws in the project.
7. What’s a delegate?
A delegate object encapsulates a reference to a system. In C++ they were referred to as function pointers.
8. How’s the DLL Hell problem solved in .NET?
Assembly versions allows the application to specify not only the library it needs to function (which was available under Win32), but also the version of the Assembly.
9. What are the ways to deploy an assembly?
An MSI installer, a CAB archive, and XCOPY command.
10. What’s a satellite assembly?
When writing a multilingual application in multi-cultural. NET, and need to deliver the core application separately from the localized modules, the localized assemblies that change the core application are called satellite assemblies.
11. What’s the difference between // comments, /* */ comments and /// comments?
Single-line, multi-line and XML documentation comments.
12. How do you generate documentation from the C# file commented properly with a command-line compiler?
Compile it with a /doc switch.
13. What’s the difference between <c> and <code> XML documentation tag?
Single line code example and multiple-line code example.
C# Interview Questions & Answers, Part 2
11. How can you sort the elements of the array in descending order?
By calling Sort() and then Reverse() methods.
12. What’s the .NET collection class that allows an element to be accessed using a unique key?
HashTable.
13. What class is underneath the SortedList class?
A sorted HashTable.
14. Will the finally block get executed if an exception has not occurred?
Yes.
15. What’s the C# syntax to catch any possible exception?
A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}.
16. Can multiple catch blocks be executed for a single try statement?
No. Once the proper catch block processed, control is transferred to the finally block (if there are any).
17. Explain the three services model commonly know as a three-tier application.
Presentation (UI), Business (logic and underlying code) and Data (from storage or other sources).
What are the variuos Enterprise Application Blocks in .NET
Exception error Handling
Caching Application Block
Data Application Block
Logging Application Block
Security Application Block
Unity Application Block
Policy Injection Application Block
Validation Application Block
