C# Test Answer 2019

1. A banking application is online. As soon as Martin finished his session, Lisa logged on and did some banking. The connection string created for each of them is as follows:

String ConnStr= «Server=BankServer;Database=BankDB;User=Martin;Password=gilbo123;»

String ConnStr= «Server=BankServer;Database=BankDB;User=Lisa;Password=kari75;»

Which of the following statements will be correct in case the connection pooling is also switched on?

Answers: • Lisa can not use someone else’s connection from the connection pool

2. Which of the following statements are false regarding the 3 timer classes provided by the .NET framework?+

a) System.Windows.Forms.Timer

b) System.Timers.Timer

c) System.Threading.Timer

Answers: • The event handler of all of the three Timers call the timer event handler on a worker thread obtained from the Common Language Runtime (CLR) thread pool.

3. Which 1. Which of the following define the rules for .NET Languages?

Answers: • CLS, or • CTS

4. Which of the following functions are used to wait for a thread to terminate?

Answers: • Join

5. _____________ helped overcome the DLL conflict faced by the C# language versions prior to .NET.

Answers: • GAC

6. What is the benefit of using a finally{} block with a try-catch statement in C#?

Answers: • The finally block is always executed before the thread is aborted.

7. In which of the following namespaces is the Assembly class defined?

Answers: • System.Reflection

8. Which of the following statements is true regarding predicate delegates in C#?

Answers: • Predicate delegates are references to functions that return true or false.

9. What is the syntax required to load and use a normal unmanaged windows DLL (e.g. kernel32.DLL) in a managed .NET C# code?

Answers: • [DllImport(”kernel32”, SetLastError=true)]

10. Which of the following is the correct way to implement deep copying of an object in C#?

Answers: • By using the System.Runtime.Serialization.Formatters.Binary.BinaryFormatter class.

11. What will be the output of the following Main program in a C# console application (Assume required namespaces are included)?

static void Main(string[] args)

{

string Invalid = “$am$it$”;

string sResult = Invalid.Trim(new char[]{‘$’});

Console.WriteLine(sResult);

Console.ReadLine();

}

Answers: • am$it

12. Which of the following is the correct way to perform a LINQ query on a DataTable object?

Answers: • var results = from myRow in myDataTable.AsEnumerable() where myRow.Field<int>(“RowNo”) == 1 select new { IID= myRow.Field<int>(“IID”), Date = myRow.Field<DateTime>(“Date”), };

13. What is the purpose of the vshost.exe file in Visual Studio?

Answers:

• It is used to improve the performance of the Visual Studio debugger.

• It is used to improve the performance of Visual Studio plugins.

• It is used to improve the performance of the C# compiler.

• It is used to load Visual Studio configuration data.

14. An Interface represents which kind of relationship?

Answers: • CAN DO

15. The .NET Framework consists of:

Answers: • The Common Language Runtime and a set of class libraries

16. An enum is defined in a program as follows:

[Flags]

public enum Permissions

{

None = 0,

Read = 1,

Write = 2,

Delete = 4

}

What will be the output of the following Main program (which has access to the enum defined above) in this C# console application (Assume required namespaces are included) :

static void Main(string[] args)

{

var permissions = Permissions.Read | Permissions.Write;

if ((permissions & Permissions.Write) == Permissions.Write)

{

Console.WriteLine(“Write”);

}

if ((permissions & Permissions.Delete) == Permissions.Delete)

{

Console.WriteLine(“Delete”);

}

if ((permissions & Permissions.Read) == Permissions.Read)

{

Console.WriteLine(“Read”);

}

Console.ReadLine();

}

Answers: • Write Read

17. Which of the following keywords prevents a class from being overridden further?

Answers: • sealed

18. Suppose there is a List of type Person with a property of LastName(string) and PopulateList is a function which returns a Generic List of type Person:

List <Person> people = PopulateList();

What does the statement below do?

people.Sort((x, y) => string.Compare(x.LastName, y.LastName));

Answers: • It will sort the string in place.

19. Which of the following will correctly remove duplicates from a List<T>?

Answers: • List<T> withDupes = LoadSomeData(); List<T> noDupes = withDupes.Distinct().ToList();