.Net Interview Questions and Answers – Part 6
51. How do you create threading in.NET? What is the namespace for that?
System.Threading; //create new thread using the thread class’s constructor Thread myThread = new Thread(new ThreadStart (someFunction));
52. What do you mean by Serialize and MarshalByRef?
Serialization is the act of saving the state of an object so that it can be recreated (i.e deserialized) at a later date.
The MarshalByRef class is part of the System.Runtime.Remoting namespace and enables us to access and use objects that reside in different application domains. It is the base class for objects that need to communicate across application domains.
MarshalByRef objects are accessed directly within their own application domain by using a proxy to communicate. With MarshalByValue the a copy of the entire object is passed across the application domain.
53. What is Asynchronous call and how it can be implemented using delegates?
A synchronous call will wait for a method to complete before program flow is resumed. With an asynchronous call the program flow continues whilst the method executes.
//create object SomeFunction objFunc = new SomeFunction(); //create delegate SomeDelegate objDel = new SomeDelegate(objFunc.FunctionA); //invoke the method asynchronously (use interface IAsyncResult) IAsyncResult asynchCall = SomeDelegate.Invoke();
54. How to create events for a control? What is custom events? How to create it?
An event is a mechanism used in a class that can be used to provide a notification when something interesting happens. (typical evens in a windows application
include: change text in textbox, double click or click a button, select an item in dropdown box).
A custom event is an event created by the user that other developers can use. For example assuming that we have a CashTransaction class and we have a bank
balance property in that class. We may want to set-up an event that provides a notification when the bank balance drops below a certain amount. In order to
produce an event the process would be roughly as follows:
Create the class for the event derived from EventArgs.
Create a delegate with a return type of void.
Create a class containing the method that will activate the event.
Create a class with methods to handle the event.
55. If you want to write your own dot net language, what steps you will you take care?
We will need to ensure that the high level code is compiled to MSIL (Microsoft intermediate language) so that it can be interpreted by the CLR.
56. Describe the diffeerence between inline and code behind – which is best in a loosely coupled solution?
The term ‘code behind’ refers to application code that is not embedded within the ASPX page and is separated out into a separate file which is then referenced
from the ASPX page. Inline code is the traditional ASP architectural model where business logic code was embedded within the ASP page. Separating the business
logic code from the presentation layer offers several advantages:
1) It allows graphic designers and web developers to work on the presentation layer whilst the application developers concentrate on the business logic.
2) The codebehind file is compiled as a single dll increasing the efficiency of the application,
3) The codebehind model offers a true OO development platform,
4) It speeds up development time as it allows developers to fully maximise the features of the .NET framework such as Cahing, ViewState, Session, Smart Navigation etc.
5) Code is much easier to maintain and susceptible for change.
6) The compiler and VS.NET provides much better support for error checking, intellisense and debugging when using the code behind model.
57. How dot net compiled code will become platform independent?
The raison d’etre for .NET was to cater for multiples languages on a single windows platform whereas the aim of Java was to be a single language on multiple platforms. The only way that .NET can be platform independent is if there is a version of the .NET framework installed on the target machine.
58. Without modifying source code if we compile again, will it be generated MSIL again?
No., Its not possible.
59. How does you handle this COM components developed in other programming languages in.NET?
use TlbImp.exe to import the COM types into your .NET project. If no type library for the COM component then use System.Runtime.InteropServices
use RegAsm.exe to call a .NET developed component in a COM application.
60. How CCW (Com Callable Wrapper) and RCW (Runtime Callable Wrappers) works?
CCW: When a COM application calls a NET object the CLR creates the CCW as a proxy since the COM application is unable to directly access the .NET object.
RCW: When a .NET application calls a COM object the CLR creates the RCW as a proxy since the .NET application is unable to directly access the .COM object.