Asp.net Ajax

Front 1

Which command can you use to find out if the page postback is from an Asynchronous postback

Back 1

ScriptManager.IsInAsyncPostback

Front 2

How can you find out which control made the Async postback?

Back 2

ScriptManager.AsyncPostbackSourceElementID

Front 3

If the update panel hijacks the postback request and turns it into Async, does this mean the page does not have to go through a full cycle during Async postback?

Back 3

The page does goes through a full life cycle of page post back

Front 4

Which two things does an update panel inject into the page after an Async postback?

Back 4

The updated contents within the update panel
ViewState for controls within the update panel

Front 5

Which two .NET classes of the SYS namespace provide the framework for issuing asynchronous PosBacks?

Back 5

Sys.WebForms.PageRequestManager
Sys.Applications

Front 6

Using ScriptManager, how do you create a proxy to an Ajax enabled web service?

Back 6

<Services>
------<asp:ServiceReference Path="~/WeatherService.svc"
</Services>

Front 7

Under ScriptManager markup, how do you specify a reference to a custom Javascript file

Back 7

<Services>
------<asp:ServiceReference Path="~/Scripts/MyCustomCode.js"
</Services>

Front 8

Instead of developing a web service, how can you enable your aspx page to dispatch calls to a page asynchronously?

Back 8

<asp:ScriptManager EnablePageMethod="true" />

Decorate the method with the [WebMethod] attribute

Invoke method using PageMethod class:
PageMethod.MethodName( );

Front 9

When making asynchronous calls how can you cancel the process in the middle?

Back 9

Sys.WebForms.PageRequestManager.abortPostBack()

This will discard the response from the server.

Front 10

What are the 5 events raised by the PageRequestManager class after an asynchronous request has been issued?

Back 10

initializeRequest
beginRequest
pageLoading
pageLoaded
endRequest

Front 11

What are the 3 events raised by Sys.Applciations? Which event initiates the postback events of the PageRequestManager class?

Back 11

init
load - initiates events of PageRequestManager
unload

Front 12

Which 3 events do you implicitly get in your script due to the presence of the ScriptManager control?

Back 12

pageInit (sender)
pageLoad (sender, args)
pageUnload (sender, args)

Front 13

What are the steps involved in an asynchronous postback using updatePanel?

Back 13

1. XMLHttpRequest is generated to the server

2. Server processes the request going through a full page life cycle and renders the output HTML

3. XMLHttpRequest extracts the HTML delta and sends to the client.

4. Client injects the received HTML into the DOM

Front 14

How does the updatePanel behave if the client does not support asynchronous postBacks?

Back 14

It falls back to normal postback

Front 15

How can you specify that the UpdatePanel renders its contents within a div or a span?

Back 15

RenderMode = "Block" generates div

RenderMode="Inline" generates span

Front 16

What's the default update mode for updatePanels?
What can you change it to?

Back 16

UpdateMode = "Always"

change to:
UpdateMode="Conditional"

Front 17

If a page has 3 update panels with their default settings, what happens to the other two panels when the third panel issues a postback?

Back 17

By default UpdateMode="Always". Therefore all update panels get updated by the postback.

Front 18

How can you programmatically make an updatePanel fire an asynchronous postback using a control residing outside the control panel?

Back 18

Call updatePanel.Update() method

Condition:
UpdateMode="Conditional"
ChildrenAsTriggers = "false"

Front 19

How can you prevent controls within an update panel from triggering a postBack request?

Back 19

Set ChildrenAsTriggers = "false"

Front 20

What type of triggers can be specified in the <Triggers> collection of an update panel?
What two attributes do these triggers take?

Back 20

<asp:AsynchronousPostBackTrigger />
<asp:PostBackTrigger/>

ControlID
EventName

Front 21

How can you have a control inside an update issue a standard postback?

Back 21

Add it to the <Triggers> collection using a <asp:PostBack/> trigger

Front 22

How can you have an external control issue an asynchronous postback for an update panel?

Back 22

Add it to the <Triggers> collection using a <asp:AsynchronousPostBack/> trigger

Front 23

What's the requirement for using Nested update panels?

Back 23

UpdateMode property must be set to "Conditional"

Front 24

If nested update panels are configured correctly, how will the behave when triggering asynchronous postbacks?

Back 24

Outer panel will update all child panels but not parent panels

Front 25

Which binding is used by JavaScript callable WCF services?

Back 25

WebHttpBinding

Front 26

What's the data format used by JavaScript callable WCF services?

Back 26

JSON

Front 27

When using JavaScript callable WCF services, what argument should be specified in the [ServiceContract] attribute?

Back 27

unique namespace

[ServiceContract(Namespace = "http://www.pluralsight.com/ws/")]

Front 28

When using JavaScript callable WCF services, what three things that need to be set in the web.config file?

Back 28

Set enableWebScript

Set aspNetCompatibilityEnabled = "true"

Use WebHttpBinding

Front 29

When using JavaScript callable WCF services, what two callback methods does the client side JavaScript proxy provide?
What argument does it provide for each callback method?

Back 29

OnSuccess (result, userData)
-------- userData would be the last argument provided in the request

OnFailure (err)

Front 30

Instead o using the ScriptManager control, how can you programmatically create a proxy for a WCF service endpoint ?

When is the proxy JavaScript file sent back to the client?

Back 30

Specify the JS paramater in script when referencing the endpoint

<script src="StockQuoteService.svc/js" />

the proxy JavaScript file sent back to the client at runtime

Front 31

How can you modify the behavior of a WCF method to return data as XML instead of JSON?

Back 31

by using the WebInvoke(ResponseFormat=WebMessageFormat.Xml) with the OperationContract attribute.

Front 32

What three client side Ajax Extensions classes are provided by the Microsoft AJAX framework for Asynchronous request?

Back 32

MicrosoftAjax.js
MicrosoftAjaxWebForms.js
MicrosoftAjaxTimer.js

Front 33

How can you combine scripts to decrease round-trips and improve efficiency?

Back 33

By using <CompositeScript>

<asp:ScriptManager>
----<CompositeScript>

--------<asp:ScriptReference name="MicrosoftAjax.js"/>
--------<asp:ScriptReference name="MicrosoftAjaxWebForms.js"/>
--------<asp:ScriptReference name="MicrosoftAjaxTimer.js"/>

----<CompositeScript>
<asp:ScriptManager>

Front 34

What object does the PageRequestManager class provide to reference a server control in JavaScript?

Back 34

$get ("ServerControlID");