CSharp Interview Questions: Part 1

  1. 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.
  2. Can you store multiple data types in System.Array?
  3. 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.
  4. How can you sort the elements of the array in descending order?
    By calling Sort() and then Reverse() methods.
  5. What’s the .NET datatype that allows the retrieval of data by a unique key?
  6. What’s class SortedList underneath?
    A sorted HashTable.
  7. Will finally block get executed if the exception had not occurred?
  8. 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 {}.
  9. 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.
  10. 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.
  11. What’s a delegate?
    A delegate object encapsulates a reference to a method. In C++ they were referred to as function pointers.
  12. What’s a multicast delegate?
    It’s a delegate that points to and eventually fires off several methods.
  13. 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.
  14. What are the ways to deploy an assembly? An MSI installer, a CAB archive, and XCOPY command.
  15. 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.
  16. What namespaces are necessary to create a localized application?
    System.Globalization, System.Resources.
  17. What’s the difference between // comments, /* */ comments and /// comments?
    Single-line, multi-line and XML documentation comments.
  18. How do you generate documentation from the C# file commented properly with a command-line compiler?
    Compile it with a /doc switch.
  19. What’s the difference between <c> and <code> XML documentation tag?

    Single line code example and multiple-line code example.
  20. Is XML case-sensitive?
    Yes, so <Student> and <student> are different elements.