Monday, 17 March 2014

Interview Q & A on Server Side Controls(Ajax,User/Custom Controls,Validations) in Asp.Net

1. What is ASP.NET AJAX?
 answer:
ASP.NET AJAX, mostly called AJAX, is a set of extensions of ASP.NET. It is developed by Microsoft to implement AJAX functionalities in Web applications. ASP.NET AJAX provides a set of components that enable the developers to develop applications that can update only a specified portion of data without refreshing the entire page. The ASP.NET AJAX works with the AJAX Library that uses object-oriented programming (OOP) to develop rich Web applications that communicate with the server using asynchronous postback.

2. What is the difference between synchronous postback and asynchronous postback?
 answer:
The difference between synchronous and asynchronous postback is as follows:

Asynchronous postback renders only the required part of the page; whereas, synchronous postback renders the entire page for any postback.

Asynchronous postback executes only one postback at a time, that is, if you have two buttons doing asynchronous postback, the actions will be performed one by one; whereas, synchronous postback executes all the actions at once.

Asynchronous postback only modifies the update panel that raises the postback; whereas, synchronous postback modifies the entire page.

3. What technologies are being used in AJAX?
 answer:
AJAX uses four technologies, which are as follows:
JavaScript
XMLHttpRequest
Document Object Model (DOM)
Extensible HTML (XHTML) and Cascading Style Sheets (CSS)

4. Why do we use the XMLHttpRequest object in AJAX?
 answer:
The XMLHttpRequest object is used by JavaScript to transfer XML and other text data between client and server. The XMLHttpRequest object allows a client-side script to perform an HTTP request. AJAX applications use the XMLHttpRequest object so that the browser can communicate to the server without requiring a postback of the entire page. In earlier versions of Internet Explorer, MSXML ActiveX component is liable to provide this functionality; whereas, Internet Explorer 7 and other browsers, such as Mozilla Firefox, XMLHttpRequest is not liable to.

5. How can we get the state of the requested process?
 answer:
XMLHttpRequest get the current state of the request operation by using the readyState property. This property checks the state of the object to determine if any action should be taken. The readyState property uses numeric values to represent the state.

6. What are the different controls of ASP.NET AJAX?
 answer:
ASP.NET AJAX includes the following controls:
ScriptManager
ScriptManagerProxy
UpdatePanel
UpdateProgress
Timer

7)How do you validate Input data on web page?
answer:
Before submitting a web page to server, Input validation on web page is one of the important task.ASP.Net provides below validation controls to validate data in web controls and shows user friendly Messages to the user.

ASP.Net validation Controls:

8)Define Validation Control in ASP.NET?
 answer:
The validation control is used to implement page level validity of data entered in the server controls. This check is done before the page is posted back to the server thus avoid round trip to the server. If data does not pass validation, it will display an error message to the user.

9)What are the differences between custom Web control and user control?
answer:

Custom Control:

1)         To be used across different applications.
2)         Good for dynamic layout.
3)         Doesn't have a visual interface.
4)         It's a .DLL (Dynamic Linked Libraries) file.
5)         It can be added to the toolbox and can be used in different applications without re-compiling.

User Control:

1)         Can be used for a particular website.
2)         Good for Static layout.
3)         Have a visual interface.
4)         It's an .ascx file.
5)         It can't be added to the toolbox and it will not have design support and loaded at runtime.

10) Differentiate between:
 answer:
Client-side and server-side validations in Web pages.

- Client-side validations happends at the client's side with the help of JavaScript and VBScript. This happens before the Web page is sent to the server.
- Server-side validations occurs place at the server side.

11)What data type does the RangeValidator control support?
 answer:
Integer, String and Date

12)Which two properties are on every validation control?
answer:
We have two common properties for every validation controls
1. Control to Validate,
2. Error Message.

14)What is validationsummary server control?where it is used?.
answer:
The ValidationSummary control allows you to summarize the error messages from all validation controls on a Web page in a single location. The summary can be displayed as a list, a bulleted list, or a single paragraph, based on the value of the DisplayMode property.

15)What are all the navigation controls available with asp.net?
 answer:
Menus
Site Maps
Tree View

16)Can you set which type of comparison you want to perform by the CompareValidator control?
answer:
Yes, by setting the Operator property of the CompareValidator control.

17)What is webpart controls?
answer:
Web Parts is an integrated set of controls for creating Web sites that enable end users to modify the content, appearance, and behavior of Web pages directly from a browser.

18.what are the facilities of webparts?
answer:
1)personalize page content
2)personalize page layout
3)Export and import controls
4)create connections
5)Manage and personalize site-level settings

19.what are the steps involved in webparts page life cycle?
answer:
1)Initialistion
2)Initialisation Complete
3)Load Complete
4)Save State Complete

20)How to Register Webuser control in webpage?
 answer:
<%@ Register TagPrefix="uc" TagName=""
    Src="Spinner.ascx" %>

21)Types of Custom controls?
answer:
Custom controls are compiled controls that act, from the client's perspective,
much like web (ASP) controls. Custom controls can be created in one of three ways:

By deriving a new custom control from an existing control (e.g., deriving your own specialized text box from asp:textbox).
 This is known as a derived custom control.
By composing a new custom control out of two or more existing controls. This is known as a composite custom control.
By deriving from the base control class, thus creating a new custom control from scratch. This is known as a full custom control.

22)How to Consume Custom control in webpage?
answer:
<%@ Register Assembly="CustomControls" 
                Namespace="CustomControls"
                TagPrefix="ccs" %>

23)Which directive we need to use to work with webusercontrol?
answer:
<% Control Language="C#"
    AutoEventWireUP="true"
    CodeFile="abc.ascx.cs"
    Inherits="MyWebUserControl"%>

24)Advantages of WebUser controls?
answer:
Reusability
Performance
EasyModifications

25)Explain any 3rd party tool for asp.net Controls?
answer:
Teleric controls
KendoUI
ComponentGallery

26)Advantages of 3rd Party tools?
answer:
ExceptionalPerformance
Developer Friendly
CrossBrowserSupport


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