41 Why does the control’s PostedFile property always show null when using HtmlInputFile control to upload files to a Web server?

· This occurs when an enctype="multipart/form-data" attribute is missing in the

tag.



42 How can the focus be set to a specific control when a Web form loads?

· This can be achieved by using client-side script:

document.forms[0].TextBox1.focus ()

The above code will set the focus to a TextBox named TextBox1 when the page loads.

43 How does System.Web.UI.Page’s IsPostBack property work?

· IsPostBack checks to see whether the HTTP request is accompanied by postback data containing a __VIEWSTATE or __EVENTTARGET parameter. If there are none, then it is not a postback.



44 What is WSDL?

· 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: www.w3.org)



45 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.





46 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.





47 Why do uploads fail while using an ASP.NET file upload control to upload large files?

· ASP.NET limits the size of file uploads for security purposes. The default size is 4 MB. This can be changed by modifying the maxRequestLength attribute of Machine.config’s element.





48 Describe the difference between inline and code behind.

· Inline code is written along side the HTML in a page. Code-behind is code written in a separate file and referenced by the .aspx page.





49 Describe the role of inetinfo.exe, aspnet_isapi.dll andaspnet_wp.exe in the page loading process.

· inetinfo.exe is theMicrosoft IIS server running, handling ASP.NET requests among other things.When an ASP.NET request is received (usually a file with .aspx extension), the ISAPI filter aspnet_isapi.dll takes care of it by passing the request tothe actual worker process aspnet_wp.exe.





50 Can you explain the difference between an ADO.NET Dataset and an ADO Recordset?

· Valid answers are:

a. A DataSet can represent an entire relational database in memory, complete with tables, relations, and views.

b. A DataSet is designed to work without any continuing connection to the original data source.

c. Data in a DataSet is bulk-loaded, rather than being loaded on demand.

d. There’s no concept of cursor types in a DataSet.

e. DataSets have no current record pointer You can use For Each loops to move through the data.

f. You can store many edits in a DataSet, and write them to the original data source in a single operation.

g. Though the DataSet is universal, other objects in ADO.NET come in different versions for different data sources.



51 What’s a bubbled event?

· When you have a complex control, like DataGrid, writing an event processing routine for each object (cell, button, row, etc.) is quite tedious. The controls can bubble up their eventhandlers, allowing the main DataGrid event handler to take care of its constituents.



52 What data types do the RangeValidator control support?

· Integer, String, and Date.

53 Explain what a diffgram is, and a good use for one?

· The DiffGram is one of the two XML formats that you can use to render DataSet object contents to XML. A good use is reading database data to an XML file to be sent to a Web Service.



54 What is the transport protocol you use to call a Web service?

· SOAP (Simple Object Access Protocol) is the preferred protocol.



55 What is ViewState?

· ViewState allows the state of objects (serializable) to be stored in a hidden field on the page. ViewState is transported to the client and back to the server, and is not stored on the server or any other external source. ViewState is used the retain the state of server-side objects between postabacks.



56 What does the "EnableViewState" property do? Why would I want it on or off?

· It allows the page to save the users input on a form across postbacks. It saves the server-side values for a given control into ViewState, which is stored as a hidden value on the page before sending the page to the clients browser. When the page is posted back to the server the server control is recreated with the state stored in viewstate.



57 What are the different types of Session state management options available with ASP.NET?

· ASP.NET provides In-Process and Out-of-Process state management. In-Process stores the session in memory on the web server. This requires the a "sticky-server" (or no load-balancing) so that the user is always reconnected to the same web server. Out-of-Process Session state management stores data in an external data source. The external data source may be either a SQL Server or a State Server service. Out-of-Process state management requires that all objects stored in session are serializable.



58 Differences Between XML and HTML?

Anyone with a fundamental grasp of XML should be able describe some of the main differences outlined in the table below

XML HTML

User definable tags Defined set of tags designed

forweb display

Content driven Format driven

End tags required for well formed End tags not required

documents

Quotes required around attributes Quotes not required

values

Slash required in empty tags Slash not required



59 Give a few examples of types of applications that can benefit from using XML.

There are literally thousands of applications that can benefit from XML technologies. The point of this question is not to have the candidate rattle off a laundry list of projects that they have worked on, but, rather, to allow the candidate to explain the rationale for choosing XML by citing a few real world examples. For instance, one appropriate answer is that XML allows content management systems to store documents independently of their format, which thereby reduces data redundancy. Another answer relates to B2B exchanges or supply chain management systems. In these instances, XML provides a mechanism for multiple companies to exchange data according to an agreed upon set of rules. A third common response involves wireless applications that require WML to render data on hand held devices.



60 What is DOM and how does it relate to XML?

o The Document Object Model (DOM) is an interface specification maintained by the W3C DOM Workgroup that defines an application independent mechanism to access, parse, or update XML data. In simple terms it is a hierarchical model that allows developers to manipulate XML documents easily Any developer that has worked extensively with XML should be able to discuss the concept and use of DOM objects freely. Additionally, it is not unreasonable to expect advanced candidates to thoroughly understand its internal workings and be able to explain how DOM differs from an event-based interface like SAX.