ASP.NET AJAX includes the following controls:
Extensible HTML (XHTML) is a markup language that provides the mixture expressions of HTML and XML. XHTML is a flexible markup language that enables automated processing by standard XML tools, which was difficult in HTML.
A Web page cannot contain more than one ScriptManager control. You can use the ScriptManagerProxy control to add scripts to other pages; however to perform such an operation, you need to work with a master page that contains the ScriptManager control. If you have only few pages that need to register to a script or a Web service, then you should remove these pages from the ScriptManager control and add them as individual pages by using the ScriptManagerProxy control. If you include the scripts on the master page by the ScriptManager control, then the items get downloaded on each page that extends the master page, even if they are not necessary.
The difference between synchronous and asynchronous postback is as follows:
You can divide the ASP.NET AJAX architecture into two components - AJAX client architecture and AJAX server architecture.
The following are the limitations of AJAX:
We can pass parameters to the server using either the GET or POST method.
The following code snippets show the example of both the methods:
Get: XmlHttpObject.Open("GET", "file1.txt", true);
Post: XmlHttpObject.Open("POST", "file2.txt", true);
No, you have to copy this file to the Bin folder of your application.
The DynamicPopulateExtender control populates the contents of a control dynamically. It enables you to send an asynchronous call to the server that dynamically populates the contents of a control. The DynamicPopulateExtender control replaces the contents of a control with the result of a Web service or page method call.
The MinimumPrefixLength property sets the minimum number of characters that must be entered before getting suggestions from the Web service.
AJAX is a built-in functionality of .NET Framework 4.@Therefore, you can run an AJAX application by just installing Microsoft Visual Studio 20@However, to use extenders in your applications, you are required to install AJAX Control Toolkit and copy the AjaxControlToolkit.dll file to the Bin directory of your application.
AJAX uses the following syntax to create an object:
var myobject = new AjaxObject("page path");
The page path is the URL of the Web page containing the object that you want to call. The URL must be of the same domain as the Web page.
AJAX uses four technologies, which are as follows:
The different states of the XMLHttpRequest object are as follows:
Client-side libraries contain built-in code to make asynchronous calls over XMLHTTP. These libraries automatically handle browser compatibility issues. These libraries are based on a programming model similar to ASP.NET.
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.
You can find out that an AJAX request has been completed by using the readyState property. If the value of this property equals to four, it me that the request has been completed and the data is available.
The UpdateProgress control is somewhat related to the UpdatePanel control. The UpdateProgress control enables you to design a user-friendly interface when a Web page consists of a number of UpdatePanel controls for partial-page rendering.
The UpdateProgress control makes you aware of the status information about the partial-page updates in the UpdatePanel control.
The UpdatePanel control specifies the portions of a Web page that can be updated together. As the UpdatePanel control refreshes only a selected part of the Web page instead of refreshing the entire page with a postback, you get more flexibility to create rich and client-centric Web applications.
Refreshing a selected part of the Web page is referred as partial-page update. You can add one or more UpdatePanel control in the Web page, which automatically participates in partial-page update without custom client script. The UpdatePanel control uses the UpdatePanel class to support the partial-page rendering.
Yes, we can nest the UpdatePanel control.
The AccordionExtender control is similar to the CollapsiblePanelExtender control. It allows you to group multiple collapsible panels in a single control. At the same time, it also manages the collapsed and expanded state of each panel; therefore, expanding one panel at a time. In other words, the AccordionExtender control does not support expanding two or more panels simultaneously. Instead, the header templates of all the panels are always visible so that you can click on any of them to display the hidden contents. By default, the AccordionExtender control opens with one panel as expanded.
No, it is not possible.
The new features included in the Microsoft AJAX library are as follows:
The Step property sets the steps for numeric increment and decrement. The default value is 1.
The following controls are introduced with the new version of AJAX Control Toolkit:
SeaDragonExtender control - Refers to the control that is used to deeply zoom the images. You can zoom in or out the image or the particular portion of the image by using the mouse. You can also create a menu over the Seadragon control. This control is helpful when you want to analyze the image closely.
AsyncFileUploadExtender control - Refers to the control that provides the facility to upload and save the files on the server asynchronously. You can check the outcome either at the server or client side.
The following validation controls are available in ASP.NET AJAX 4.0:
The ConformOnFormSubmit property determines whether or not the confirm dialog box should wait when the form is submitted for display.
You should not use AJAX if:
The Timer control is used with an UpdatePanel control to allow partial-page updates at a specified interval. It is mostly used when a periodically partial-page update for one or more UpdatePanel controls is required without refreshing the entire page.
When the Timer control initiates a postback, the Tick event is raised on the server for which you can provide an event handler to perform the actions when the page is submitted to the server. The Tick event occurs when the time specified in the interval property has elapsed and the page is posted on the server. You can add one or more Timer controls on a Web page. Usually the entire page requires only a single Timer control; however, you can use multiple Timer controls, if the UpdatePanel controls are being updated at different intervals.
ASP.NET 4.0 AJAX includes several new features that provide more functionality to a user.
These features are as follows:
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.