17 Interview Questions and Answers - .NET Remoting

1. What’s a Windows process?
   It’s an application that’s running and had been allocated memory.
2. What’s typical about a Windows process in regards to memory allocation?
   Each process is allocated its own block of available RAM space, no process can access another process’ code or data. If the process crashes, it dies alone without taking the entire OS or a bunch of other applications down.
3. Why do you call it a process? What’s different between process and application in .NET, not common computer usage, terminology?
   A process is an instance of a running application. An application is an executable on the hard drive or network. There can be numerous processes launched of the same application (5 copies of Word running), but 1 process can run just 1 application.
4. What distributed process frameworks outside .NET do you know?
   Distributed Computing Environment/Remote Procedure Calls (DEC/RPC), Microsoft Distributed Component Object Model (DCOM), Common Object Request Broker Architecture (CORBA), and Java Remote Method Invocation (RMI).
5. What are possible implementations of distributed applications in .NET?
   .NET Remoting and ASP.NET Web Services. If we talk about the Framework Class Library, noteworthy classes are in System.Runtime.Remoting and System.Web.Services.
6. When would you use .NET Remoting and when Web services?
   Use remoting for more efficient exchange of information when you control both ends of the application. Use Web services for open-protocol-based information exchange when you are just a client or a server with the other end belonging to someone else.
7. What’s a proxy of the server object in .NET Remoting?
   It’s a fake copy of the server object that resides on the client side and behaves as if it was the server. It handles the communication between real server object and the client object. This process is also known as marshaling.
8. What are remotable objects in .NET Remoting?
   Remotable objects are the objects that can be marshaled across the application domains. You can marshal by value, where a deep copy of the object is created and then passed to the receiver. You can also marshal by reference, where just a reference to an existing object is passed.
9. What are channels in .NET Remoting?
   Channels represent the objects that transfer the other serialized objects from one application domain to another and from one computer to another, as well as one process to another on the same box. A channel must exist before an object can be transferred.
10. What security measures exist for .NET Remoting in System.Runtime.Remoting?
    None. Security should be taken care of at the application level. Cryptography and other security techniques can be applied at application or server level.
11. What is a formatter?
    A formatter is an object that is responsible for encoding and serializing data into messages on one end, and deserializing and decoding messages into data on the other end.
12. Choosing between HTTP and TCP for protocols and Binary and SOAP for formatters, what are the trade-offs?
    Binary over TCP is the most effiecient, SOAP over HTTP is the most interoperable.
13. What’s SingleCall activation mode used for?
    If the server object is instantiated for responding to just one single request, the request should be made in SingleCall mode.
14. What’s Singleton activation mode?
    A single object is instantiated regardless of the number of clients accessing it. Lifetime of this object is determined by lifetime lease.
15. How do you define the lease of the object?
    By implementing ILease interface when writing the class code.
16. Can you configure a .NET Remoting object via XML file?
    Yes, via machine.config and application level .config file (or web.config in ASP.NET). Application-level XML settings take precedence over machine.config.
17. How can you automatically generate interface for the remotable object in .NET with Microsoft tools?
    Use the Soapsuds tool.

Posted in: Interview Questions | Tags: interview questions and answers questions interview answers q&a .net .net remoting c# c sharp proxy remotable xml automatical

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.NET Windows Forms Interview Questions and Answers

1. Write a simple Windows Forms MessageBox statement.
   System.Windows.Forms.MessageBox.Show
   ("Hello, Windows Forms");
2. Can you write a class without specifying namespace? Which namespace does it belong to by default??
   Yes, you can, then the class belongs to global namespace which has no name. For commercial products, naturally, you wouldn’t want global namespace.
3. You are designing a GUI application with a window and several widgets on it. The user then resizes the app window and sees a lot of grey space, while the widgets stay in place. What’s the problem?
   One should use anchoring for correct resizing. Otherwise the default property of a widget on a form is top-left, so it stays at the same location when resized.
4. How can you save the desired properties of Windows Forms application?
   .config files in .NET are supported through the API to allow storing and retrieving information. They are nothing more than simple XML files, sort of like what .ini files were before for Win32 apps.
5. So how do you retrieve the customized properties of a .NET application from XML .config file?
   Initialize an instance of AppSettingsReader class. Call the GetValue method of AppSettingsReader class, passing in the name of the property and the type expected. Assign the result to the appropriate variable.
6. Can you automate this process?
   In Visual Studio yes, use Dynamic Properties for automatic .config creation, storage and retrieval.
7. My progress bar freezes up and dialog window shows blank, when an intensive background process takes over.
   Yes, you should’ve multi-threaded your GUI, with taskbar and main form being one thread, and the background process being the other.
8. What’s the safest way to deploy a Windows Forms app?
   Web deployment: the user always downloads the latest version of the code; the program runs within security sandbox, properly written app will not require additional security privileges.
9. Why is it not a good idea to insert code into InitializeComponent method when working with Visual Studio?
   The designer will likely throw it away; most of the code inside InitializeComponent is auto-generated.
10. What’s the difference between WindowsDefaultLocation and WindowsDefaultBounds? WindowsDefaultLocation tells the form to start up at a location selected by OS, but with internally specified size. WindowsDefaultBounds delegates both size and starting position choices to the OS.
11. What’s the difference between Move and LocationChanged? Resize and SizeChanged?
    Both methods do the same, Move and Resize are the names adopted from VB to ease migration to C#.
12. How would you create a non-rectangular window, let’s say an ellipse?
    Create a rectangular form, set the TransparencyKey property to the same value as BackColor, which will effectively make the background of the form transparent. Then set the FormBorderStyle to FormBorderStyle.None, which will remove the contour and contents of the form.
13. How do you create a separator in the Menu Designer?
    A hyphen ‘-’ would do it. Also, an ampersand ‘&\’ would underline the next letter.
14. How’s anchoring different from docking?
    Anchoring treats the component as having the absolute size and adjusts its location relative to the parent form. Docking treats the component location as absolute and disregards the component size. So if a status bar must always be at the bottom no matter what, use docking. If a button should be on the top right, but change its position with the form being resized, use anchoring.

Simple Questions:

Posted in: Interview Questions General | Tags: interview questions and answers questions interview answers q&a .net c# c sharp xml winform rectangular window menu designer docking anchor dock deploy specify namespace config

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Routing in ASP.NET 4

ASP.NET 4 adds built-in support for using routing with Web Forms. Routing lets you configure an application to accept request URLs that do not map to physical files. Instead, you can use routing to define URLs that are meaningful to users and that can help with search-engine optimization (SEO) for your application. For example, the URL for a page that displays product categories in an existing application might look like the following example:

http://website/products.aspx?categoryid=12

By using routing, you can configure the application to accept the following URL to render the same information:

http://website/products/software

Routing has been available starting with ASP.NET 3.5 SP1. However, ASP.NET 4 includes some features that make it easier to use routing, including the following:

· The PageRouteHandler class, which is a simple HTTP handler that you use when you define routes. The class passes data to the page that the request is routed to.

· The new properties HttpRequest.RequestContext and Page.RouteData (which is a proxy for the HttpRequest.RequestContext.RouteData object). These properties make it easier to access information that is passed from the route.

· The following new expression builders, which are defined in System.Web.Compilation.RouteUrlExpressionBuilder and System.Web.Compilation.RouteValueExpressionBuilder:

· RouteUrl, which provides a simple way to create a URL that corresponds to a route URL format within an ASP.NET server control.

· RouteValue, which provides a simple way to extract information from the RouteContext object.

· The RouteParameter class, which makes it easier to pass data contained in a RouteContext object to a query for a data source control (similar to FormParameter).

Routing for Web Forms Pages

The following example shows how to define a Web Forms route by using the new MapPageRoute method of the Route class:

public class Global : System.Web.HttpApplication

{

void Application_Start(object sender, EventArgs e)

{

RouteTable.Routes.MapPageRoute("SearchRoute",

"search/{searchterm}", "~/search.aspx");

RouteTable.Routes.MapPageRoute("UserRoute",

"users/{username}", "~/users.aspx");

}

}

ASP.NET 4 Beta 2 introduces the MapPageRoute method. The following example is equivalent to the SearchRoute definition shown in the previous example, but uses the PageRouteHandler class.

RouteTable.Routes.Add("SearchRoute", new Route("search/{searchterm}",

new PageRouteHandler("~/search.aspx")));

The code in the example maps the route to a physical page (in the first route, to ~/search.aspx). The first route definition also specifies that the parameter named searchterm should be extracted from the URL and passed to the page.

The MapPageRoute method supports the following method overloads:

· MapPageRoute(string routeName, string routeUrl, string physicalFile, bool checkPhysicalUrlAccess)

· MapPageRoute(string routeName, string routeUrl, string physicalFile, bool checkPhysicalUrlAccess, RouteValueDictionary defaults)

· MapPageRoute(string routeName, string routeUrl, string physicalFile, bool checkPhysicalUrlAccess, RouteValueDictionary defaults, RouteValueDictionary constraints)

The checkPhysicalUrlAccess parameter specifies whether the route should check the security permissions for the physical page being routed to (in this case, search.aspx) and the permissions on the incoming URL (in this case, search/{searchterm}). If the value of checkPhysicalUrlAccess is false, only the permissions of the incoming URL will be checked. These permissions are defined in the Web.config file with settings such as the following:

<configuration>

<location path="search.aspx">

<system.web>

<authorization>

<allow roles="admin"/>

<deny users="*"/>

</authorization>

</system.web>

</location>

<location path="search">

<system.web>

<authorization>

<allow users="*"/>

</authorization>

</system.web>

</location>

</configuration>

In the example configuration, access is denied to the physical page search.aspx for all users except those who are in the admin role. When the checkPhysicalUrlAccess parameter is set to true (which is its default value), only admin users are allowed to access the URL /search/{searchterm}, because the physical page search.aspx is restricted to users in that role. If checkPhysicalUrlAccess is set to false and the site is configured as shown in the previous example, all authenticated users are allowed to access the URL /search/{searchterm}.

Posted in: asp.net | Tags: xml asp.net asp.net 4.0 eventargs routing pageroutehandler httprequest requestcontext routevalueexpressionbuilder web form page authorization location configuration

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what is XMLRPC

XML RPC is a easiest way to kick start writing of Web Services, where applications "talk" across networks (intranets or internet) .
Creating an XML-RPC Web service with Perl is almost as easy as CGI scripting. This blog is a tutorial on using XML RPC with Perl. It uses Perl's Frontier::RPC library to create simple clients and servers.
WHAT IS RPC?Remote Procedure Call (RPC) is a mechanism to call functions Remote Procedure Calls (RPC) are not a new concept they have been in Unix class oses for a long time and on Windows OS too. A client/server system, RPCs have traditionally been procedures called in a program on one machine that go over the network to some RPC server that actually implements the called procedure.
The RPC server bundles up the results of the procedure and sends those results back to the caller. The calling program then continues executing. While this system requires a lot of overhead and latency, it also allows less powerful machines to access high powered resourcesWHAT IS XML RPC? A RPC call earlier was to be sent in propritery formats that can be understood only by the specific client and the server. With the evolution of XML as a standard for information interchange.XML can be used to encode RPC Calls and use it in communication.an implementation of XML RPC would be as follows a client accessing a server encodes it's request into XML and uses simple HTTP protocol to transfer the XMLAt the server side the XML is parsed and procedure are called with parameters that came from the client.
The exciting part about XML-RPC is that it can cross programming language and operating system platforms, allowing clients and servers written in different languages to work together. Perl clients can talk to Java servers; Python listeners can service PHP requests; you can even write XML-RPC programs in bad, old C.
XML-RPC is extremely easy to work with because the details of the XML translations are hidden from the user, unless, of course, you are implementing your own XML-RPC library. There are two important aspects of this protocol that you should keep in mind when building your middleware. XML-RPC is built on HTTP and, like ordinary Web traffic, its stateless conversations are of the request and response variety.
There is no built-in support for transactions or encryption. The other important detail to remember is that XML-RPC has a finite set of datatypes. Client procedure arguments and listener return values are mapped in a non-extendable XML subset. In practice, though, XML-RPC's datatypes are often flexible enough to do complex tasks. The XML RPC Data Types:XML-RPC tag Description a sequence of characters signed or unsigned 32-bit integer values true(1) or false(0) signed double precision floating point numbers date and time (but no timezone) a base64 encoded string a container for a sequence of datatypes a container for key-value pairs XML RPC is a good mechanism to start writing Web Services, a more modern refined brother of XML RPC is SOAP.

Posted in: General | Tags: xml xml rpc rpc

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top 10 Giant list of XML interview questions and answers

1. What is XML?

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 meta language—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 meta language for
text document markup (ISO 8879).

2. What is a markup language?

A markup language is a set of words and symbols for describing
the identity of pieces of a document (for example ‘this is
a paragraph’, ‘this is a heading’, ‘this
is a list’, ‘this is the caption of this figure’,
etc). Programs can use this with a style sheet to create output
for screen, print, audio, video, Braille, etc.
Some markup languages (eg those used in word processors) only describe
appearances (’this is italics’, ‘this is bold’),
but this method can only be used for display, and is not normally
re-usable for anything else.

3. Where should I use XML?

Its goal is to enable generic SGML to be served, received, and
processed on the Web in the way that is now possible with HTML.
XML has been designed for ease of implementation and for interoperability
with both SGML and HTML.
Despite early attempts, browsers never allowed other SGML, only
HTML (although there were plugins), and they allowed it (even encouraged
it) to be corrupted or broken, which held development back for over
a decade by making it impossible to program for it reliably. XML
fixes that by making it compulsory to stick to the rules, and by
making the rules much simpler than SGML.

But XML is not just for Web pages: in fact it’s very rarely used
for Web pages on its own because browsers still don’t provide reliable
support for formatting and transforming it. Common uses for XML
include:
Information identification because you can define your own markup,
you can define meaningful names for all your information items.
Information storage because XML is portable and non-proprietary,
it can be used to store textual information across any platform.
Because it is backed by an international standard, it will remain
accessible and processable as a data format. Information structure
XML can therefore be used to store and identify any kind of (hierarchical)
information structure, especially for long, deep, or complex document
sets or data sources, making it ideal for an information-management
back-end to serving the Web. This is its most common Web application,
with a transformation system to serve it as HTML until such time
as browsers are able to handle XML consistently. Publishing the
original goal of XML as defined in the quotation at the start of
this section. Combining the three previous topics (identity, storage,
structure) means it is possible to get all the benefits of robust
document management and control (with XML) and publish to the Web
(as HTML) as well as to paper (as PDF) and to other formats (eg
Braille, Audio, etc) from a single source document by using the
appropriate stylesheets. Messaging and data transfer XML is also
very heavily used for enclosing or encapsulating information in
order to pass it between different computing systems which would
otherwise be unable to communicate. By providing a lingua franca
for data identity and structure, it provides a common envelope for
inter-process communication (messaging). Web services Building on
all of these, as well as its use in browsers, machine-processable
data can be exchanged between consenting systems, where before it
was only comprehensible by humans (HTML). Weather services, e-commerce
sites, blog newsfeeds, AJaX sites, and thousands of other data-exchange
services use XML for data management and transmission, and the web
browser for display and interaction.

4. Why is XML such an important development?

It removes two constraints which were holding back Web developments:
1. dependence on a single, inflexible document type (HTML) which
was being much abused for tasks it was never designed for;

2. the complexity of full SGML, whose syntax allows many powerful
but hard-to-program options.
XML allows the flexible development of user-defined document types.
It provides a robust, non-proprietary, persistent, and verifiable
file format for the storage and transmission of text and data both
on and off the Web; and it removes the more complex options of SGML,
making it easier to program for.

5. Describe the differences between XML and HTML.

It’s amazing how many developers claim to be proficient programming
with XML, yet do not understand the basic 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
User definable tags

Content driven
End tags required for well formed documents
Quotes required around attributes values
Slash required in empty tags

HTML
Defined set of tags designed for web display

Format driven
End tags not required
Quotes not required
Slash not required

6. Describe the role that XSL can play when dynamically
generating HTML pages from a relational database.

Even if candidates have never participated in a project involving
this type of architecture, they should recognize it as one of the
common uses of XML. Querying a database and then formatting the
result set so that it can be validated as an XML document allows
developers to translate the data into an HTML table using XSLT rules.
Consequently, the format of the resulting HTML table can be modified
without changing the database query or application code since the
document rendering logic is isolated to the XSLT rules.

7. What is SGML?

SGML is the Standard Generalized Markup Language (ISO 8879:1986),
the international standard for defining descriptions of the structure
of different types of electronic document. There is an SGML FAQ
from David Megginson at http://math.albany.edu:8800/hm/sgml/cts-faq.htmlFAQ;
and Robin Cover’s SGML Web pages are at http://www.oasis-open.org/cover/general.html.
For a little light relief, try Joe English’s ‘Not the SGML
FAQ’ at http://www.flightlab.com/~joe/sgml/faq-not.txtFAQ.
SGML is very large, powerful, and complex. It has been in heavy
industrial and commercial use for nearly two decades, and there
is a significant body of expertise and software to go with it.
XML is a lightweight cut-down version of SGML which keeps enough
of its functionality to make it useful but removes all the optional
features which made SGML too complex to program for in a Web environment.

8. Aren’t XML, SGML, and HTML all the same thing?

Not quite; SGML is the mother tongue, and has been used for describing
thousands of different document types in many fields of human activity,
from transcriptions of ancient Irish manuscripts to the technical
documentation for stealth bombers, and from patients’ clinical records
to musical notation. SGML is very large and complex, however, and
probably overkill for most common office desktop applications.

XML is an abbreviated version of SGML, to make it easier to use
over the Web, easier for you to define your own document types,
and easier for programmers to write programs to handle them. It
omits all the complex and less-used options of SGML in return for
the benefits of being easier to write applications for, easier to
understand, and more suited to delivery and interoperability over
the Web. But it is still SGML, and XML files may still be processed
in the same way as any other SGML file (see the question on XML
software).
HTML is just one of many SGML or XML applications—the one
most frequently used on the Web.
Technical readers may find it more useful to think of XML as being
SGML– rather than HTML++.

9. Who is responsible for XML?

XML is a project of the World Wide Web Consortium (W3C), and the
development of the specification is supervised by an XML Working
Group. A Special Interest Group of co-opted contributors and experts
from various fields contributed comments and reviews by email.
XML is a public format: it is not a proprietary development of any
company, although the membership of the WG and the SIG represented
companies as well as research and academic institutions. The v1.0
specification was accepted by the W3C as a Recommendation on Feb
10, 1998.

10. Why is XML such an important development?

It removes two constraints which were holding back Web developments:
1. dependence on a single, inflexible document type (HTML) which
was being much abused for tasks it was never designed for;
2. the complexity of full question A.4, SGML, whose syntax allows
many powerful but hard-to-program options.
XML allows the flexible development of user-defined document types.
It provides a robust, non-proprietary, persistent, and verifiable
file format for the storage and transmission of text and data both
on and off the Web; and it removes the more complex options of SGML,
making it easier to program for.

Posted in: Interview Questions | Tags: interview questions and answers interview xml markup language html xsl xslt sgml

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