Collection of Interview Questions on  CSharp

Code

try
            {
                try
                {
                    throw new ApplicationException();
                }
                finally
                {
                    throw new SystemException();

                }

            }
            catch (Exception ex)
            {

                Console.WriteLine(ex.GetType().Name);
            }

Output

SystemException.

Reason

When ApplicationException is raise, it will goes to within the  exception stack, and the  finally block also will run and throw system exception, now system exception also goes to within the exception stack.But when we are print within catch, system exception is most recently added, this is will be retrieved first from stack.so SystemException is result for above code.

Answer:

var

If you are use the var keyword, then it valid type against right side value on declaration time

Example:

var data = "name";            
Console.WriteLine(data);

Here var will be string type at compile time.

dynamic

If you are use the dynamic keyword, the type will be decide on run time.

Example:

dynamic data = "name";
data = 8;
Console.WriteLine(data);

it will compile without any error, at run time data variable type is a int than string.because in the second line of code, you have change to string to in value on right hand side.

Answer:

If you want to prevent a class to create subclass, the class must be sealed. Most of the security classes are sealed.

Sample Code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    public sealed class TryCatch
    {
        public void SaveEmployee(string empID)
        {

               // few line of code here            
            
        }
    }
}

Answer:

The Array has two methods to perform copy operation such as Clone() and CopyTo().The Clone() method returns a new array (a shallow copy) object containing all the elements in the original array. The CopyTo() method copies the elements into another existing array. Both perform a shallow copy. A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array. A deep copy (which neither of these methods performs) would create a new instance of each element's object, resulting in a different, yet identacle object.