Learning Curve…

Archive for August 2011

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If you are using the Dev Express Page control (ASPxPageControl) and receiving the below error :-
“Cannot unregister UpdatePanel with ID ‘UpdatePanel1’ since it was not registered with the ScriptManager. This might occur if the UpdatePanel was removed from the control tree and later added again, which is not supported. Parameter name: updatePanel”
                                                                                                                                                                                                                        In ASPxPageControl , Set  ViewStateMode property to Enabled and EnableHierarchyRecreation to “false” :-

ViewStateMode=”Disabled” and EnableHierarchyRecreation=”false”

Your ASPxPageControl tag should be something like this :-

<dx:ASPxPageControl ID=”ASPxPageControl1″ runat=”server” ActiveTabIndex=”0″ EnableHierarchyRecreation=”false” ClientIDMode=”AutoID” EnableCallBacks=”true” ClientInstanceName=”ASPxPageControl1″ ViewStateMode=”Enabled”>

<TabPages> ………..</TabPages></dx:ASPxPageControl>

This will solve your issue.

Happy Coding!!!

Question:-What is XML ?
Answer: XML is the Extensible Markup Language. It improves the functionality of the Web by letting you identify your information in a more accurate, flexible, and adaptable way. It is extensible because it is not a fixed format like HTML (which is a single, predefined markup language). Instead, XML is actually a metalanguage—a language for describing other languages—which lets you design your own markup languages for limitless different types of documents. XML can do this because it’s written in SGML, the international standard metalanguage for text document markup (ISO 8879).

Question:-What is DOM?
Answer: Document Object Model (DOM) is a W3C specification that defines a standard (abstract) programming API to build, navigate and update XML documents. It is a “tree-structure-based” interface. As per the DOM specification, the XML parsers (such as MSXML or Xerces), load the entire XML document into memory, before it can be processed. XPath is used to navigate randomly in the document, and various DOM methods are used to create and update (add elements, delete elements, add/remove attributes, etc.) the XML documents.
Question:-What is XPath?
Answer: XML Path Language (XPath) is a W3C specification that defines syntax for addressing parts of XML document. XML document is considered as a logical tree structure, and syntax based on this consideration is used to address elements and attributes at any level in the XML document. For example, considering the XML document described above in answer to question 2, /abc:Employees/abc:Emp/@EmpID XPath expression can be used to access the EmpID attribute under the (first) Emp element under the Employees document element. XPath is used in various other specifications such as XSLT.

Question:-What is XHTML?
Answer: Is simple words, XHTML, or Extensible HTML, is HTML 4 with XML rules applied to it (each begin tag must have an end tag, attribute values in single/double quotes, etc.). However, the overall vision of XHTML is much more than that. In addition to using XML syntax for HTML, XHTML also encloses specifications such as XHTML Basic (minimal set of modules for devices such as PDAs), XForms (represents the next generation of forms for the Web, and separates presentation, logic, and data), XML Events (provides XML languages with the ability to uniformly integrate event listeners and associated event handlers), etc.

Question:-What is XML Parser ?
Answer: Microsoft’s XML parser is a COM component that comes with Internet Explorer 5 and higher. Once you have installed Internet Explorer, the parser is available to scripts.
Microsoft’s XML parser supports all the necessary functions to traverse the node tree, access the nodes and their attribute values, insert and delete nodes, and convert the node tree back to XML.

To create an instance of Microsoft’s XML parser with JavaScript, use the following code:
var xmlDoc=new ActiveXObject(“Microsoft.XMLDOM”)

To create an instance of Microsoft’s XML parser with VBScript, use the following code:
set xmlDoc=CreateObject(“Microsoft.XMLDOM”)

To create an instance of Microsoft’s XML parser in an ASP page (using VBScript), use the following code:
set xmlDoc=Server.CreateObject(“Microsoft.XMLDOM”)

The following code loads an existing XML document (“note.xml”) into Microsoft’s XML parser:
<script type=”text/javascript”>
var xmlDoc=new ActiveXObject(“Microsoft.XMLDOM”)


Question:- Some Limitation or Disadvantage of XML?
Answer: XML markup has a few disadvantages:
It can be verbose unless element and attribute names are chosen with care. In large documents the markup overhead need not be large, but in short messages it can be significantly more than the actual data, especially when the element or attribute names are concocted by machine.

Overlapping markup is not permitted (an element cannot start inside one element and end inside another): element markup must nest hierarchically.

Some of the software is truly mediocre.

Question:- How to add in XML document through XSL ?
Answer: XSL (the eXtensible Stylesheet Language) is far more sophisticated than CSS. One way to use XSL is to transform XML into HTML before it is displayed by the browser as demonstrated in these examples:
Below is a fraction of the XML file. The second line,
<?xml-stylesheet type=”text/xsl” href=”simple.xsl”?>, links the XML file to the XSL file:
<?xml version=”1.0″ encoding=”ISO-8859-1″?>
<?xml-stylesheet type=”text/xsl” href=”simple.xsl”?>
<name>Belgian Waffles</name>
two of our famous Belgian Waffles

Question:- How do I convert my existing HTML documents into XML?
Answer: Tidy is a command-line utility which runs on a wide variety of operating systems; it uses various command-line switches (parameters) to control its processing. At a minimum, it simply cleans up your HTML by ensuring that elements are properly nested and so on; it also warns you if your HTML uses non-standard code that’s likely to cause cross-browser compatibility problems. One of the most useful command-line options is -asxml (“as XML,” see?), which does what you seem to be asking. It will properly balance elements, per usual, but it also adds some extra information to the document. For instance, it tacks on an XML declaration, , and a statement, which unambiguously mark this as an XML document. To the root html element it also adds a namespace-declaring attribute that identifies all elements in the document as conforming to the specific XML vocabulary known as XHTML. It even forces all element names to lowercase, since the XHTML standard requires it.

If you’re asking about converting HTML to a less generic form of XML than XHTML, your task may turn out to be quite complex. For example, if you’ve been using HTML to mark up customer invoices, not only the customer’s name but also their number, item(s) ordered, quantity, and price are probably all wrapped up inside <p> and </p> tags. How do you know which “kind of paragraph” contains a given kind of information, so you can turn one instance of the p element into a custname element, another into custnumber, another into price, and so on? If you’ve been using CSS for styling your HTML, you may have supplied the different p elements with (etc.) attributes and so on; if that’s the case, you may be able to generate meaningful XML using an XSLT stylesheet. There may also be customized software to do the sort of conversion you want. Otherwise you’re probably looking down the barrel of an ugly gun.

Question:- What is a schema? What are the limitations of a DTD?
Answer: SCHEMA is nothing but METADATA. The schema holds all the information of the xml file that is to be deployed in the project. Metatdata is nothing about data about data since we know that xml is used for data representation language we will be able to understand what metadata is. Metadata includes the tags that is going to be exchanged to and fro from another xml file. DTD (DATA TYPE DEFINITION ) which supervises two conditions namely well formedness and closeness of the xml file. So the user should be aware of what tags he was put into use of this xml file ‘A’ should be intimated to another application’s XML file ‘B’, by then our xml file will interact with the another xml file, this is the major limitation and mandatory issue that the developers should follow.

Question: Define Protocols that helps Web Services ?
Answer:From my point of view Web Services used three protocols for interacting with the clients.Http-Post,Http-Get,SOAP.

Question: Explain functioning of Web Services Protocols ?
Answer: Http-Get:– This is standard protocol that helps client to communicate with server with HTTP.When client send a request to server via HTTP request and reuired parameter are attached with the querystring.Example:-
http://www.dotnetquestion.info/dotnet/interview.aspx?id=pervej&cast=munjal and we get the value from querystring.

Http-Post:-This is same as Http-Get but the diffrence is that in place of sending parameters onto the URL information is send with HTTP request message with some extra information which contains Parameters and their values.This Protocols is limited to sending name/value pairs.

SOAP:-The only diffrence is that its relies on the XML as compares to Http-Get,Http-Post.SOAP can send not only the name/value pairs but also some complex object also as for example datatypes,class,objects.SOAP can also uses request/reponse model as Http-Get,Http-post but it is not limited to Request/Response it can also send types of message.Because its uses XML that is pure text so firewalls not created so much problem because its easily converted in to HTML. .

Question: Why do some web service classes derive from System.Web.WebServices while others do not ?
Answer: Those Web Service classes which employ objects like Application, Session, Context, Server, and User have to derive from System.Web.WebServices. If it does not use these objects, it is not necessary to be derived from it.

Question: What is WSDL ?
Answer: WSDL is an XML format for describing network services as a set of endpoints operating on messages containing either document-oriented or procedure-oriented information. The operations and messages are described abstractly, and then bound to a concrete network protocol and message format to define an endpoint. Related concrete endpoints are combined into abstract endpoints (services). (Source: http://www.w3.org).

Question: What is the standard you use to wrap up a call to a Web service ?
Answer: HTTP with SOAP.

Question: Explain Web Services ?
Answer: Web services are programmable business logic components that provide access to functionality through the Internet. Standard protocols like HTTP can be used to access them. Web services are based on the Simple Object Access Protocol (SOAP), which is an application of XML. Web services are given the .asmx extension..

Question: What are VSDISCO files ?
VSDISCO files are DISCO files that enable dynamic discovery of Web Services. ASP.NET links the VSDISCO to a HTTP handler that scans the host directory and subdirectories for ASMX and DISCO files and returns a dynamically generated DISCO document. A client who requests a VSDISCO file gets back what appears to be a static DISCO document.

Question: What is UDDI ?
UDDI stands for Universal Description, Discovery, and Integration. It is like an “Yellow Pages” for Web Services. It is maintained by Microsoft, IBM, and Ariba, and is designed to provide detailed information regarding registered Web Services for all vendors. The UDDI can be queried for specific Web Services.

Question: Is it possible to generate the source code for an ASP.NET Web service from a WSDL ?
The Wsdl.exe tool (.NET Framework SDK) can be used to generate source code for an ASP.NET web service with its WSDL link.

Example: wsdl /server http://api.google.com/GoogleSearch.wsdl.

Question: Can you give an example of when it would be appropriate to use a web service as opposed to a non-serviced .NET component ?
When to Use Web Services:

(i)Communicating through a Firewall When building a distributed application with 100s/1000s of users spread over multiple locations, there is always the problem of communicating between client and server because of firewalls and proxy servers. Exposing your middle tier components as Web Services and invoking the directly from a Windows UI is a very valid option.

(ii)Application Integration When integrating applications written in various languages and running on disparate systems. Or even applications running on the same platform that have been written by separate vendors.

(iii)Business-to-Business Integration This is an enabler for B2B intergtation which allows one to expose vital business processes to authorized supplier and customers. An example would be exposing electronic ordering and invoicing, allowing customers to send you purchase orders and suppliers to send you invoices electronically.

(iv)Software Reuse This takes place at multiple levels. Code Reuse at the Source code level or binary componet-based resuse. The limiting factor here is that you can reuse the code but not the data behind it. Webservice overcome this limitation. A scenario could be when you are building an app that aggregates the functionality of serveral other Applicatons. Each of these functions could be performed by individual apps, but there is value in perhaps combining the the multiple apps to present a unifiend view in a Portal or Intranet.

Question: What are Service Oriented Architectures (SOA) ?
SOA describes an information technology architecture that enables distributed computing environments with many different types of computing platforms and applications. Web services are one of the technologies that help make SOAs possible. As a concept, SOA has been around since the 1980s, but many early IT technologies failed to achieve the goal of linking different types of applications and systems. By making early investments with .NET, Microsoft has helped provide the building blocks that today are putting many enterprise customers on the path to successfully implementing SOAs. With SOAs, companies can benefit from the unimpeded flow of information that is the hallmark of connected systems.

Question: What is .NET Passport ?
.NET Passport is a Web-based service that is designed to make signing in to Web sites fast and easy. Passport enables participating sites to authenticate a user with a single set of sign-in credentials, alleviating the need for users to remember numerous passwords and user names.

jQuery  is a new kind of JavaScript Library.jQuery is a fast and concise JavaScript Library that simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development. jQuery is designed to change the way that you write JavaScript.

Click  here  to download jQuery book (Wrox – Beginning JavaScript and CSS Development with jQuery).

StarUML – .StarUML is an open source project to develop fast, flexible, extensible, featureful, and freely-available UML/MDA platform . The goal of the StarUML project is to build a software modeling tool.

—  StarUML Features

1. Accurate UML standard model.
2. Open software model format.
3. Excellent extensibility.
4. Software model verification function.
5. Useful Add-Ins
6. True MDA support.

 —  System Requirements

• Intel® Pentium® 233MHz or higher
• Windows® 2000, Windows XP™, or higher
• Microsoft® Internet Explorer 5.0 or higher
• 128 MB RAM (256MB recommended)
• 110 MB hard disc space (150MB space recommended)
• CD-ROM drive
• SVGA or higher resolution monitor (1024×768 recommended)
• Mouse or other pointing device

Click here to Download starUML book .


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