ASP.Net Interview Questions 4

By | May 13, 2014

When you’re running a component within ASP.NET, what process is it running within on Windows XP? Windows 2000? Windows 2003? On Windows 2003 (IIS 6.0) running in native mode, the component is running within the w3wp.exe process associated with the application pool which has been configured for the web application containing the component. On Windows 2003 in IIS 5.0 emulation mode, 2000, or XP, it’s running within the IIS helper process whose name I do not remember, it being quite a while since I last used IIS 5.0.

What does aspnet_regiis -i do ? Aspnet_regiis.exe is The ASP.NET IIS Registration tool allows an administrator or installation program to easily update the script maps for an ASP.NET application to point to the ASP.NET ISAPI version associated with the tool. The tool can also be used to display the status of all installed versions of ASP. NET, register the ASP.NET version coupled with the tool, create client-script directories, and perform other configuration operations.   When multiple versions of the .NET Framework are executing side-by-side on a single computer, the ASP.NET ISAPI version mapped to an ASP.NET application determines which version of the common language runtime is used for the application.   The tool can be launched with a set of optional parameters. Option “i” Installs the version of ASP.NET associated with Aspnet_regiis.exe and updates the script maps at the IIS metabase root and below. Note that only applications that are currently mapped to an earlier version of ASP.NET are affected

What is a PostBack? The process in which a Web page sends data back to the same page on the server.

What is ViewState? How is it encoded? Is it encrypted? Who uses ViewState? ViewState is the mechanism ASP.NET uses to keep track of server control state values that don’t otherwise post back as part of the HTTP form. ViewState Maintains the UI State of a Page   ViewState is base64-encoded.  It is not encrypted but it can be encrypted by setting EnableViewStatMAC=”true” & setting the machineKey validation type to 3DES.  If you want to NOT maintain the ViewState, include the directive < %@ Page EnableViewState=”false” % > at the top of an .aspx page or add the attribute EnableViewState=”false” to any control.

What is the < machinekey > element and what two ASP.NET technologies is it used for? Configures keys to use for encryption and decryption of forms authentication cookie data and view state data, and for verification of out-of-process session state identification.There fore 2 ASP.Net technique in which it is used are Encryption/Decryption & Verification

What three Session State providers are available in ASP.NET 1.1? What are the pros and cons of each? ASP.NET provides three distinct ways to store session data for your application: in-process session state, out-of-process session state as a Windows service, and out-of-process session state in a SQL Server database. Each has it advantages.  1.In-process session-state mode Limitations:  * When using the in-process session-state mode, session-state data is lost if aspnet_wp.exe or the application domain restarts.  * If you enable Web garden mode in the < processModel > element of the application’s Web.config file, do not use in-process session-state mode. Otherwise, random data loss can occur. Advantage:  * in-process session state is by far the fastest solution. If you are storing only small amounts of volatile data in session state, it is recommended that you use the in-process provider. 2. The State Server simply stores session state in memory when in out-of-proc mode. In this mode the worker process talks directly to the State Server 3. SQL mode, session states are stored in a SQL Server database and the worker process talks directly to SQL. The ASP.NET worker processes are then able to take advantage of this simple storage service by serializing and saving (using .NET serialization services) all objects within a client’s Session collection at the end of each Web request  Both these out-of-process solutions are useful primarily if you scale your application across multiple processors or multiple computers, or where data cannot be lost if a server or process is restarted.

What is the difference between HTTP-Post and HTTP-Get? As their names imply, both HTTP GET and HTTP POST use HTTP as their underlying protocol. Both of these methods encode request parameters as name/value pairs in the HTTP request. The GET method creates a query string and appends it to the script’s URL on the server that handles the request. The POST method creates a name/value pairs that are passed in the body of the HTTP request message.

Name and describe some HTTP Status Codes and what they express to the requesting client. When users try to access content on a server that is running Internet Information Services (IIS) through HTTP or File Transfer Protocol (FTP), IIS returns a numeric code that indicates the status of the request. This status code is recorded in the IIS log, and it may also be displayed in the Web browser or FTP client. The status code can indicate whether a particular request is successful or unsuccessful and can also reveal the exact reason why a request is unsuccessful. There are 5 groups ranging from 1xx – 5xx of http status codes exists. 101 – Switching protocols. 200 – OK. The client request has succeeded 302 – Object moved. 400 – Bad request. 500.13 – Web server is too busy.

Explain < @OutputCache% > and the usage of VaryByParam, VaryByHeader. OutputCache is used to control the caching policies of an ASP.NET page or user control. To cache a page @OutputCache directive should be defined as follows < %@ OutputCache Duration=”100″ VaryByParam=”none” % > VaryByParam: A semicolon-separated list of strings used to vary the output cache. By default, these strings correspond to a query string value sent with GET method attributes, or a parameter sent using the POST method. When this attribute is set to multiple parameters, the output cache contains a different version of the requested document for each specified parameter. Possible values include none, *, and any valid query string or POST parameter name. VaryByHeader: A semicolon-separated list of HTTP headers used to vary the output cache. When this attribute is set to multiple headers, the output cache contains a different version of the requested document for each specified header.

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