Technical Interview Questions

What is the use of fixed statement

The fixed statement sets a pointer to a managed variable and “pins” that variable during the execution of statement.

Without fixed, pointers to managed variables would be of little use since garbage collection could relocate the variables unpredictably. (In fact, the C# compiler will not allow you to set a pointer to a managed variable except in a fixed statement.)

Eg: Class A { public int i; }

A objA = new A; // A is a .net managed type

fixed(int *pt = &objA.i) // use fixed while using pointers with managed

Which class use to Read/Write data to memory

MemoryStream

It is a nonbuffered stream whose encapsulated data is directly accessible in memory(RAM not files on disk).

 

To Configure .Net for JIT activation what do you do

Actually JIT activation is required for COM+ components which can be done by setting JustInTimeActivation attribute to true (choice A). For .net applications / components JIT comes in by default.

 

Which method is used by COM+ to ascertain whether class can be pooled

CanBePooled

 

How do you import Activex component in to .NET

Where does the version dependencies recorded

Inside an assembly’s manifest

 

How do you refer parent classes in C#

This keyword is used for reffering current object and Base keyword is used for referring parrent class. so ans. is C

 

Which attribute you generally find on top of main method

[ STAThread ]

 

How do you make a class not instantiable

Making class as Abstract

 

In a multilevel hierarchy how are the constructors are called

TopDown

Which method is actually called ultimately when Console.WriteLine( ) is invoked

AppendFormat() method is called.

 

What happens when you create an arraylist as ArrayList Arr=new ArrayList()

Once it will reach size 16 addding element in the arraylist, it will be automatically double the size.

 

What is the output of Vectors.RemoveAt(1)

Removes the object at position 1

 

GetEnumerator( ) of Ienumerable interface returns

GetEnumerator() returns a reference to System.Collections.Ienumerator class which allows a simple iteration over a collection

 

How do you add objects to hashtable

Which method is implicitly called when an object is created

When an object is created Constructor is get called first. A default constructor is created automatically if we do not create a constructor inside a class.

 

Which of the following statement is invalid with regards to constructor

Constructors should have the same name as class name

Constructors have to be public so that class can be instantiated

Constructors can not be overloaded

 

Constructors can not be static

C# supports two types of constructor, a class constructor (static constructor) and an instance constructor (non-static constructor).