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Sunday, October 12, 2008
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c# interview questions
http://blogs.crsw.com/mark/articles/252.aspx
ASP.NET Interview Questions&Answers
Question:-What do you mean by Share Point Portal ?
Answer: Here I have taken information regarding Share Point Portal Server 2003 provides mainly access to the crucial business information and applications.With the help of Share Point Server we can server information between Public Folders, Data Bases, File Servers and the websites that are based on Windows server 2003. This Share Point Portal is integrated with MSAccess and Windows servers,So we can get a Wide range of document management functionality. We can also create a full featured portal with readymade navigation and structure.
Question:-What is cross page posting in ASP.NET2.0 ?
Answer: When we have to post data from one page to another in application we used server.transfer method but in this the URL remains the same but in cross page posting there is little different there is normal post back is done but in target page we can access values of server control in the source page.This is quite simple we have to only set the PostBackUrl property of Button,LinkButton or imagebutton which specifies the target page.In target page we can access the PreviousPage property.And we have to use the @PreviousPageType directive.We can access control of PreviousPage by using the findcontrol method.When we set the PostBackURL property ASP.NET framework bind the HTML and Javascript function automatically.
Question: What you thing about the WebPortal ?
Answer: Web portal is nothing but a page that allows a user to customize his/her homepage. We can use Widgets to create that portal we have only to drag and drop widgets on the page. The user can set his Widgets on any where on the page where he has to get them. Widgets are nothing but a page area that helps particular function to response. Widgets example are address books, contact lists, RSS feeds, clocks, calendars, play lists, stock tickers, weather reports, traffic reports, dictionaries, games and another such beautiful things that we can not imagine. We can also say Web Parts in Share Point Portal. These are one of Ajax-Powered.
Question: How to start Outlook,NotePad file in AsP.NET with code ?
Answer: Here is the syntax to open outlook or notepad file in ASP.NET VB.NET Process.Start("Notepad.exe") Process.Start("msimn.exe"); C#.NET System.Diagnostics.Process.Start("msimn.exe"); System.Diagnostics.Process.Start("Notepad.exe");
Question: What is the purpose of IIS ?
Answer: We can call IIS(Internet Information Services) a powerful Web server that helps us creating highly reliable, scalable and manageable infrastructure for Web application which runs on Windows Server 2003. IIS helps development center and increase Web site and application availability while lowering system administration costs. It also runs on Windows NT/2000 platforms and also for above versions. With IIS, Microsoft includes a set of programs for building and administering Web sites, a search engine, and support for writing Web-based applications that access database. IIS also called http server since it process the http request and gets http response.
Question: What is main difference between GridLayout and FormLayout ?
Answer: GridLayout helps in providing absolute positioning of every control placed on the page.It is easier to devlop page with absolute positioning because control can be placed any where according to our requirement.But FormLayout is little different only experience Web Devloper used this one reason is it is helpful for wider range browser.If there is absolute positioning we can notice that there are number of DIV tags.But in FormLayout whole work are done through the tables.
Question: How Visual SourceSafe helps Us ?
Answer: One of the powerful tool provided by Microsoft to keep up-to-date of files system its keeps records of file history once we add files to source safe it can be add to database and the changes ade by diffrenet user to this files are maintained in database from that we can get the older version of files to.This also helps in sharing,merging of files.
Question:-Can you define what is SharePoint and some overview about this ?
Answer: SharePoint helps workers for creating powerful personalized interfaces only by dragging and drop pre-defined Web Part Components. And these Web Parts components also helps non programmers to get information which care and customize the appearance of Web pages. To under stand it we take an example one Web Part might display a user's information another might create a graph showing current employee status and a third might show a list of Employees Salary. This is also possible that each functions has a link to a video or audio presentation.So now Developers are unable to create these Web Part components and make them available to SharePoint users.
Question:-What is different between WebUserControl and in WebCustomControl ?
Answer: Web user controls :- Web User Control is Easier to create and another thing is that its support is limited for users who use a visual design tool one gud thing is that its contains static layout one more thing a seprate copy is required for each application.
Web custom controls:-Web Custom Control is typical to create and gud for dynamic layout and another thing is it have full tool support for user and a single copy of control is required because it is placed in Global Assembly cache.
Question:-What is Sandbox in SQL server and explain permission level in Sql Server ?
Answer: Sandbox is place where we run trused program or script which is created from the third party. There are three type of Sandbox where user code run.
Safe Access Sandbox:-Here we can only create stored procedure,triggers,functions,datatypes etc.But we doesnot have acess memory ,disk etc.
External Access Sandbox:-We cn access File systems outside the box. We can not play with threading,memory allocation etc.
Unsafe Access Sandbox:-Here we can write unreliable and unsafe code.
Question:-How many types of cookies are there in .NET ?
Answer: Two type of cookeies.
a) single valued eg request.cookies(”UserName”).value=”dotnetquestion”
b)Multivalued cookies. These are used in the way collections are used example
request.cookies(”CookiName”)(”UserName”)=”dotnetquestionMahesh”
request.cookies(”CookiName”)(”UserID”)=”interview″
Question: When we get Error 'HTTP 502 Proxy Error' ?
Answer: We get this error when we execute ASP.NET Web pages in Visual Web Developer Web server, because the URL randomly select port number and proxy servers did not recognize the URL and return this error. To resolve this problem we have to change settings in Internet Explorer to bypass the proxy server for local addresses, so that the request is not sent to the proxy.
Question:-What do you mean by three-tier architecture?
Answer: The three-tier architecture was comes into existence to improve management of code and contents and to improve the performance of the web based applications.There are mainly three layers in three-tier architecture.the are define as follows
(1)Presentation
(2)Business Logic
(3)Database
(1)First layer Presentation contains mainly the interface code, and this is shown to user. This code could contain any technology that can be used on the client side like HTML, JavaScript or VBScript etc.
(2)Second layer is Business Logic which contains all the code of the server-side .This layer have code to interact with database database and to query, manipulate, pass data to user interface and handle any input from the UI as well.
(3)Third layer Data represents the data store like MS Access, SQL Server, an XML file, an Excel file or even a text file containing data also some addtional database are also added to that layers.
Question: What is Finalizer in .NET define Dispose and Finalize ?
Answer: We can say that Finalizer are the methods that's helps in cleanp the code that is executed before object is garbage collected .The process is called finalization . There are two methods of finalizer Dispose and Finalize .There is little diffrenet between two of this method .
When we call Dispose method is realse all the resources hold by an object as well as all the resorces hold by the parent object.When we call Dispose method it clean managed as well as unmanaged resources.
Finalize methd also cleans resources but finalize call dispose clears only the unmanged resources because in finalization the garbase collecter clears all the object hold by managed code so finalization fails to prevent thos one of methd is used that is: GC.SuppressFinalize.
Question: Define SMTPclient class in DotNet framework class libarary ?
Answer: Each classes in dotnet framework inclue some properties,method and events.These properties ,methods and events are member of a class.SMTPclient class mainly concern with sending mail.This class contain the folling member.
Properties:-
Host:-The name or IP address of email server.
Port:-Port that is use when sending mail.
Methods:-
Send:-Enables us to send email synchronously.
SendAsynchronous:-Enables us to send an email asynchronously.
Event:-
SendCompleted:-This event raised when an asynchronous send opertion completes.
Question: What is late binding ?
Answer: When code interacts with an object dynamically at runtime .because our code literally doesnot care what type of object it is interacting and with the methods thats are supported by object and with the methods thats are supported by object .The type of object is not known by the IDE or compiler ,no Intellisense nor compile-time syntax checking is possible but we get unprecedented flexibilty in exchange.if we enable strict type checking by using option strict on at the top of our code modules ,then IDE and compiler will enforce early binding behaviour .By default Late binding is done.
Question:-Does .NET CLR and SQL SERVER run in different process ?
Answer: Dot Net CLR and all .net realtes application and Sql Server run in same process or we can say that that on the same address because there is no issue of speed because if these two process are run in different process then there may be a speed issue created one process goes fast and other slow may create the problem.
Question:-What is Com Marshler and its importance in .NET ?
Answer: Com Marshler is one of useful component of CLR. Its Task is to marshal data between Managed and Unmanaged environment .It helps in representation of data accross diffrenet execution enviroment.It performs the conversion of data format between manage and unmanaged code.By the helps of Com Marshlar CLR allows manage code to interoperate with unmanaged code.
Question: What is CSU and its description ?
Answer: CSU stands for comma separate values also called comma delimited.It is plain text file which stores spreadsheets or basic datatype in very simple format.One record in each line and each field separted with comma's it is often used to transfer large ammount spreadsheet data or database information between program.
Question: The IHttpHandler and IHttpHandlerFactory interfaces ?
Answer: The IHttpHandler interface is implemented by all the handlers. The interface consists of one property called IsReusable. The IsReusable property gets a value indicating whether another request can use the IHttpHandler instance. The method ProcessRequest() allows you to process the current request. This is the core place where all your code goes. This method receives a parameter of type HttpContext using which you can access the intrinsic objects such as Request and Response. The IHttpHandlerFactory interface consists of two methods - GetHandler and ReleaseHandler. The GetHandler() method instantiates the required HTTP handler based on some condition and returns it back to ASP.NET. The ReleaseHandler() method allows the factory to reuse an existing handler.
Question: what is Viewstate?
Answer:View state is used by the ASP.NET page framework to automatically save the values of the page and of each control just prior to rendering to the page. When the page is posted, one of the first tasks performed by page processing is to restore view state.
State management is the process by which you maintain state and page information over multiple requests for the same or different pages.
Client-side options are:
| * The ViewState property | * Query strings |
| * Hidden fields | * Cookies |
Server-side options are:
| * Application state | * Session state | * DataBase |
Use the View State property to save data in a hidden field on a page. Because ViewState stores data on the page, it is limited to items that can be serialized. If you want to store more complex items in View State, you must convert the items to and from a string.
ASP.NET provides the following ways to retain variables between requests:
Context.Handler object Use this object to retrieve public members of one Web form’s class from a subsequently displayed Web form.
Query strings Use these strings to pass information between requests and responses as part of the Web address. Query strings are visible to the user, so they should not contain secure information such as passwords.
Cookies Use cookies to store small amounts of information on a client. Clients might refuse cookies, so your code has to anticipate that possibility.
View state ASP.NET stores items added to a page’s ViewState property as hidden fields on the page.
Session state Use Session state variables to store items that you want keep local to the current session (single user).
Application state Use Application state variables to store items that you want be available to all users of the application.
Answer: While excuting the page, it will go under the fallowing steps(or fires the events) which collectivly known as Page Life cycle.
Page_Init -- Page Initialization
LoadViewState -- View State Loading
LoadPostData -- Postback data processing
Page_Load -- Page Loading
RaisePostDataChangedEvent -- PostBack Change Notification
RaisePostBackEvent -- PostBack Event Handling
Page_PreRender -- Page Pre Rendering Phase
SaveViewState -- View State Saving
Page_Render -- Page Rendering
Page_UnLoad -- Page Unloading
Question: What is Satellite Assemblies ?
Answer: Satellite assemblies are often used to deploy language-specific resources for an application. These language-specific assemblies work in side-by-side execution because the application has a separate product ID for each language and installs satellite assemblies in a language-specific subdirectory for each language. When uninstalling, the application removes only the satellite assemblies associated with a given language and .NET Framework version. No core .NET Framework files are removed unless the last language for that .NET Framework version is being removed. For example, English and Japanese editions of the .NET Framework version 1.1 share the same core files. The Japanese .NET Framework version 1.1 adds satellite assemblies with localized resources in a \ja subdirectory. An application that supports the .NET Framework version 1.1, regardless of its language, always uses the same core runtime files.
Question: What is CAS ?
Answer:CAS: CAS is the part of the .NET security model that determines whether or not a piece of code is allowed to run, and what resources it can use when it is running. For example, it is CAS that will prevent a .NET web applet from formatting your hard disk. How does CAS work? The CAS security policy revolves around two key concepts - code groups and permissions. Each .NET assembly is a member of a particular code group, and each code group is granted the permissions specified in a named permission set. For example, using the default security policy, a control downloaded from a web site belongs to the 'Zone - Internet' code group, which adheres to the permissions defined by the 'Internet' named permission set. (Naturally the 'Internet' named permission set represents a very restrictive range of permissions.)
Question: Automatic Memory Management ?
Answer: Automatic Memory Management: From a programmer's perspective, this is probably the single biggest benefit of the .NET Framework. No, I'm not kidding. Every project I've worked on in my long career of DOS and Windows development has suffered at some point from memory management issues. Proper memory management is hard. Even very good programmers have difficulty with it. It's entirely too easy for a small mistake to cause a program to chew up memory and crash, sometimes bringing the operating system to a screeching halt in the process.
Programmers understand that they're responsible for releasing any memory that they allocate, but they're not very good at actually doing it. In addition, functions that allocate memory as a side effect abound in the Windows API and in the C runtime library. It's nearly impossible for a programmer to know all of the rules. Even when the programmer follows the rules, a small memory leak in a support library can cause big problems if called enough.
The .NET Framework solves the memory management problems by implementing a garbage collector that can keep track of allocated memory references and release the memory when it is no longer referenced. A large part of what makes this possible is the blazing speed of today's processors. When you're running a 2 GHz machine, it's easy to spare a few cycles for memory management. Not that the garbage collector takes a huge number of cycles--it's incredibly efficient.
The garbage collector isn't perfect and it doesn't solve the problem of mis-managing other scarce resources (file handles, for example), but it relieves programmers from having to worry about a huge source of bugs that trips almost everybody up in other programming environments.
On balance, automatic memory management is a huge win in almost every situation.
Question: What Language familar to CLR?
Answer: Any language that can be compiled into Microsoft Intermediate Language (MSIL) is considered a .NET-compliant language. Following are a few of the popular .NET-compliant languages supported by CLR:
ASP>NET Interview Questions&Answers
Question:-What do you mean by Share Point Portal ?
Answer: Here I have taken information regarding Share Point Portal Server 2003 provides mainly access to the crucial business information and applications.With the help of Share Point Server we can server information between Public Folders, Data Bases, File Servers and the websites that are based on Windows server 2003. This Share Point Portal is integrated with MSAccess and Windows servers,So we can get a Wide range of document management functionality. We can also create a full featured portal with readymade navigation and structure.
Question:-What is cross page posting in ASP.NET2.0 ?
Answer: When we have to post data from one page to another in application we used server.transfer method but in this the URL remains the same but in cross page posting there is little different there is normal post back is done but in target page we can access values of server control in the source page.This is quite simple we have to only set the PostBackUrl property of Button,LinkButton or imagebutton which specifies the target page.In target page we can access the PreviousPage property.And we have to use the @PreviousPageType directive.We can access control of PreviousPage by using the findcontrol method.When we set the PostBackURL property ASP.NET framework bind the HTML and Javascript function automatically.
Question: What you thing about the WebPortal ?
Answer: Web portal is nothing but a page that allows a user to customize his/her homepage. We can use Widgets to create that portal we have only to drag and drop widgets on the page. The user can set his Widgets on any where on the page where he has to get them. Widgets are nothing but a page area that helps particular function to response. Widgets example are address books, contact lists, RSS feeds, clocks, calendars, play lists, stock tickers, weather reports, traffic reports, dictionaries, games and another such beautiful things that we can not imagine. We can also say Web Parts in Share Point Portal. These are one of Ajax-Powered.
Question: How to start Outlook,NotePad file in AsP.NET with code ?
Answer: Here is the syntax to open outlook or notepad file in ASP.NET VB.NET Process.Start("Notepad.exe") Process.Start("msimn.exe"); C#.NET System.Diagnostics.Process.Start("msimn.exe"); System.Diagnostics.Process.Start("Notepad.exe");
Question: What is the purpose of IIS ?
Answer: We can call IIS(Internet Information Services) a powerful Web server that helps us creating highly reliable, scalable and manageable infrastructure for Web application which runs on Windows Server 2003. IIS helps development center and increase Web site and application availability while lowering system administration costs. It also runs on Windows NT/2000 platforms and also for above versions. With IIS, Microsoft includes a set of programs for building and administering Web sites, a search engine, and support for writing Web-based applications that access database. IIS also called http server since it process the http request and gets http response.
Question: What is main difference between GridLayout and FormLayout ?
Answer: GridLayout helps in providing absolute positioning of every control placed on the page.It is easier to devlop page with absolute positioning because control can be placed any where according to our requirement.But FormLayout is little different only experience Web Devloper used this one reason is it is helpful for wider range browser.If there is absolute positioning we can notice that there are number of DIV tags.But in FormLayout whole work are done through the tables.
Question: How Visual SourceSafe helps Us ?
Answer: One of the powerful tool provided by Microsoft to keep up-to-date of files system its keeps records of file history once we add files to source safe it can be add to database and the changes ade by diffrenet user to this files are maintained in database from that we can get the older version of files to.This also helps in sharing,merging of files.
Question:-Can you define what is SharePoint and some overview about this ?
Answer: SharePoint helps workers for creating powerful personalized interfaces only by dragging and drop pre-defined Web Part Components. And these Web Parts components also helps non programmers to get information which care and customize the appearance of Web pages. To under stand it we take an example one Web Part might display a user's information another might create a graph showing current employee status and a third might show a list of Employees Salary. This is also possible that each functions has a link to a video or audio presentation.So now Developers are unable to create these Web Part components and make them available to SharePoint users.
Question:-What is different between WebUserControl and in WebCustomControl ?
Answer: Web user controls :- Web User Control is Easier to create and another thing is that its support is limited for users who use a visual design tool one gud thing is that its contains static layout one more thing a seprate copy is required for each application.
Web custom controls:-Web Custom Control is typical to create and gud for dynamic layout and another thing is it have full tool support for user and a single copy of control is required because it is placed in Global Assembly cache.
Question:-What is Sandbox in SQL server and explain permission level in Sql Server ?
Answer: Sandbox is place where we run trused program or script which is created from the third party. There are three type of Sandbox where user code run.
Safe Access Sandbox:-Here we can only create stored procedure,triggers,functions,datatypes etc.But we doesnot have acess memory ,disk etc.
External Access Sandbox:-We cn access File systems outside the box. We can not play with threading,memory allocation etc.
Unsafe Access Sandbox:-Here we can write unreliable and unsafe code.
Question:-How many types of cookies are there in .NET ?
Answer: Two type of cookeies.
a) single valued eg request.cookies(”UserName”).value=”dotnetquestion”
b)Multivalued cookies. These are used in the way collections are used example
request.cookies(”CookiName”)(”UserName”)=”dotnetquestionMahesh”
request.cookies(”CookiName”)(”UserID”)=”interview″
Question: When we get Error 'HTTP 502 Proxy Error' ?
Answer: We get this error when we execute ASP.NET Web pages in Visual Web Developer Web server, because the URL randomly select port number and proxy servers did not recognize the URL and return this error. To resolve this problem we have to change settings in Internet Explorer to bypass the proxy server for local addresses, so that the request is not sent to the proxy.
Question:-What do you mean by three-tier architecture?
Answer: The three-tier architecture was comes into existence to improve management of code and contents and to improve the performance of the web based applications.There are mainly three layers in three-tier architecture.the are define as follows
(1)Presentation
(2)Business Logic
(3)Database
(1)First layer Presentation contains mainly the interface code, and this is shown to user. This code could contain any technology that can be used on the client side like HTML, JavaScript or VBScript etc.
(2)Second layer is Business Logic which contains all the code of the server-side .This layer have code to interact with database database and to query, manipulate, pass data to user interface and handle any input from the UI as well.
(3)Third layer Data represents the data store like MS Access, SQL Server, an XML file, an Excel file or even a text file containing data also some addtional database are also added to that layers.
Question: What is Finalizer in .NET define Dispose and Finalize ?
Answer: We can say that Finalizer are the methods that's helps in cleanp the code that is executed before object is garbage collected .The process is called finalization . There are two methods of finalizer Dispose and Finalize .There is little diffrenet between two of this method .
When we call Dispose method is realse all the resources hold by an object as well as all the resorces hold by the parent object.When we call Dispose method it clean managed as well as unmanaged resources.
Finalize methd also cleans resources but finalize call dispose clears only the unmanged resources because in finalization the garbase collecter clears all the object hold by managed code so finalization fails to prevent thos one of methd is used that is: GC.SuppressFinalize.
Question: Define SMTPclient class in DotNet framework class libarary ?
Answer: Each classes in dotnet framework inclue some properties,method and events.These properties ,methods and events are member of a class.SMTPclient class mainly concern with sending mail.This class contain the folling member.
Properties:-
Host:-The name or IP address of email server.
Port:-Port that is use when sending mail.
Methods:-
Send:-Enables us to send email synchronously.
SendAsynchronous:-Enables us to send an email asynchronously.
Event:-
SendCompleted:-This event raised when an asynchronous send opertion completes.
Question: What is late binding ?
Answer: When code interacts with an object dynamically at runtime .because our code literally doesnot care what type of object it is interacting and with the methods thats are supported by object and with the methods thats are supported by object .The type of object is not known by the IDE or compiler ,no Intellisense nor compile-time syntax checking is possible but we get unprecedented flexibilty in exchange.if we enable strict type checking by using option strict on at the top of our code modules ,then IDE and compiler will enforce early binding behaviour .By default Late binding is done.
Question:-Does .NET CLR and SQL SERVER run in different process ?
Answer: Dot Net CLR and all .net realtes application and Sql Server run in same process or we can say that that on the same address because there is no issue of speed because if these two process are run in different process then there may be a speed issue created one process goes fast and other slow may create the problem.
Question:-What is Com Marshler and its importance in .NET ?
Answer: Com Marshler is one of useful component of CLR. Its Task is to marshal data between Managed and Unmanaged environment .It helps in representation of data accross diffrenet execution enviroment.It performs the conversion of data format between manage and unmanaged code.By the helps of Com Marshlar CLR allows manage code to interoperate with unmanaged code.
Question: What is CSU and its description ?
Answer: CSU stands for comma separate values also called comma delimited.It is plain text file which stores spreadsheets or basic datatype in very simple format.One record in each line and each field separted with comma's it is often used to transfer large ammount spreadsheet data or database information between program.
Question: The IHttpHandler and IHttpHandlerFactory interfaces ?
Answer: The IHttpHandler interface is implemented by all the handlers. The interface consists of one property called IsReusable. The IsReusable property gets a value indicating whether another request can use the IHttpHandler instance. The method ProcessRequest() allows you to process the current request. This is the core place where all your code goes. This method receives a parameter of type HttpContext using which you can access the intrinsic objects such as Request and Response. The IHttpHandlerFactory interface consists of two methods - GetHandler and ReleaseHandler. The GetHandler() method instantiates the required HTTP handler based on some condition and returns it back to ASP.NET. The ReleaseHandler() method allows the factory to reuse an existing handler.
Question: what is Viewstate?
Answer:View state is used by the ASP.NET page framework to automatically save the values of the page and of each control just prior to rendering to the page. When the page is posted, one of the first tasks performed by page processing is to restore view state.
State management is the process by which you maintain state and page information over multiple requests for the same or different pages.
Client-side options are:
| * The ViewState property | * Query strings |
| * Hidden fields | * Cookies |
Server-side options are:
| * Application state | * Session state | * DataBase |
Use the View State property to save data in a hidden field on a page. Because ViewState stores data on the page, it is limited to items that can be serialized. If you want to store more complex items in View State, you must convert the items to and from a string.
ASP.NET provides the following ways to retain variables between requests:
Context.Handler object Use this object to retrieve public members of one Web form’s class from a subsequently displayed Web form.
Query strings Use these strings to pass information between requests and responses as part of the Web address. Query strings are visible to the user, so they should not contain secure information such as passwords.
Cookies Use cookies to store small amounts of information on a client. Clients might refuse cookies, so your code has to anticipate that possibility.
View state ASP.NET stores items added to a page’s ViewState property as hidden fields on the page.
Session state Use Session state variables to store items that you want keep local to the current session (single user).
Application state Use Application state variables to store items that you want be available to all users of the application.
Answer: While excuting the page, it will go under the fallowing steps(or fires the events) which collectivly known as Page Life cycle.
Page_Init -- Page Initialization
LoadViewState -- View State Loading
LoadPostData -- Postback data processing
Page_Load -- Page Loading
RaisePostDataChangedEvent -- PostBack Change Notification
RaisePostBackEvent -- PostBack Event Handling
Page_PreRender -- Page Pre Rendering Phase
SaveViewState -- View State Saving
Page_Render -- Page Rendering
Page_UnLoad -- Page Unloading
Question: What is Satellite Assemblies ?
Answer: Satellite assemblies are often used to deploy language-specific resources for an application. These language-specific assemblies work in side-by-side execution because the application has a separate product ID for each language and installs satellite assemblies in a language-specific subdirectory for each language. When uninstalling, the application removes only the satellite assemblies associated with a given language and .NET Framework version. No core .NET Framework files are removed unless the last language for that .NET Framework version is being removed. For example, English and Japanese editions of the .NET Framework version 1.1 share the same core files. The Japanese .NET Framework version 1.1 adds satellite assemblies with localized resources in a \ja subdirectory. An application that supports the .NET Framework version 1.1, regardless of its language, always uses the same core runtime files.
Question: What is CAS ?
Answer:CAS: CAS is the part of the .NET security model that determines whether or not a piece of code is allowed to run, and what resources it can use when it is running. For example, it is CAS that will prevent a .NET web applet from formatting your hard disk. How does CAS work? The CAS security policy revolves around two key concepts - code groups and permissions. Each .NET assembly is a member of a particular code group, and each code group is granted the permissions specified in a named permission set. For example, using the default security policy, a control downloaded from a web site belongs to the 'Zone - Internet' code group, which adheres to the permissions defined by the 'Internet' named permission set. (Naturally the 'Internet' named permission set represents a very restrictive range of permissions.)
Question: Automatic Memory Management ?
Answer: Automatic Memory Management: From a programmer's perspective, this is probably the single biggest benefit of the .NET Framework. No, I'm not kidding. Every project I've worked on in my long career of DOS and Windows development has suffered at some point from memory management issues. Proper memory management is hard. Even very good programmers have difficulty with it. It's entirely too easy for a small mistake to cause a program to chew up memory and crash, sometimes bringing the operating system to a screeching halt in the process.
Programmers understand that they're responsible for releasing any memory that they allocate, but they're not very good at actually doing it. In addition, functions that allocate memory as a side effect abound in the Windows API and in the C runtime library. It's nearly impossible for a programmer to know all of the rules. Even when the programmer follows the rules, a small memory leak in a support library can cause big problems if called enough.
The .NET Framework solves the memory management problems by implementing a garbage collector that can keep track of allocated memory references and release the memory when it is no longer referenced. A large part of what makes this possible is the blazing speed of today's processors. When you're running a 2 GHz machine, it's easy to spare a few cycles for memory management. Not that the garbage collector takes a huge number of cycles--it's incredibly efficient.
The garbage collector isn't perfect and it doesn't solve the problem of mis-managing other scarce resources (file handles, for example), but it relieves programmers from having to worry about a huge source of bugs that trips almost everybody up in other programming environments.
On balance, automatic memory management is a huge win in almost every situation.
Question: What Language familar to CLR?
Answer: Any language that can be compiled into Microsoft Intermediate Language (MSIL) is considered a .NET-compliant language. Following are a few of the popular .NET-compliant languages supported by CLR:
Tuesday, July 29, 2008
Saturday, March 29, 2008
| Dasavatharam – KSR opens up with a special image |
| March 29, 2008 |
He couldn't be busier with pressing commitments for Dasavatharam's post production works. However, K.S. Ravikumar still found time to spill the beans feeding fodder to the undernourished media for lack of Dasavatharam staple. In an exclusive interview to the Economic Times daily, K.S.R provided a cursory glance as to what to expect from the movie and stated that since the visual graphics content appear for two and half hours of the movie, the project was being delayed. Although he did not dwell too much into the details of the storyline, an image of Dasavatharam was published in the daily. The image, as shown here, has the all-muscle Kamal, in an Iyengar makeover trying with all his might to possibly topple over or perhaps support what could be a statuette. Inside source say that this scene is of paramount importance to the way script opens up. Having said that, it is also significant to note that the movie was shot in sets made to recreate the Tsunami aftermath. Kamal too talking about the movie, said that he was very happy about the way the script has shaped up. He also conveyed that they have tried to convey a message that the world was changing into a global village, without going overboard and not compromising on the entertainment factor. |
Introduction
Creating your first web service is incredibly easy. In fact, by using the wizards in Visual Studio. NET you can have your first service up and running in minutes with no coding.
For this example I have created a service called MyService in the /WebServices directory on my local machine. The files will be created in the /WebServices/MyService directory.
A new namespace will be defined called MyService, and within this namespace will be a set of classes that define your Web Service. By default the following classes will be created:
| Global (in global.asax) | Derived from HttpApplication. This file is the ASP.NET equivalent of a standard ASP global.asa file. |
| WebService1 (in WebService1.cs) | Derived from System.Web.Services.WebService. This is your WebService class that allows you to expose methods that can be called as WebServices. |
There are also a number of files created:
| AssemblyInfo.cs | Contains version and configuration information for your assembly. |
| web.config | Defines how your application will run (debug options, the use of cookies etc). |
| MyService.disco | Discovery information for your service. |
| WebService1.asmx | Your WebService URL. Navigate to this file in a browser and you will get back a user-friendly page showing the methods available, the parameters required and the return values. Forms are even provided allowing you to test the services through the web page. |
| bin\MyService.dll | The actual WebService component. This is created when you build the service. |
The class for your service that is created by default is called (in this case) WebService1, and is within the MyService namespace. The code is partially shown below.
namespace MyService
{
...
/// <summary>
/// Summary description for WebService1.
/// </summary>
[WebService(Namespace="http://codeproject.com/webservices/",
Description="This is a demonstration WebService.")]
public class WebService1 : System.Web.Services.WebService
{
public WebService1()
{
//CODEGEN: This call is required by the ASP+ Web Services Designer
InitializeComponent();
}
...
[WebMethod]
public string HelloWorld()
{
return "Hello World";
}
}
}
A default method HelloWorld is generated and commented out. Simply uncomment and build the project. Hey Presto, you have a walking talking WebService.
A WebService should be associated with a namespace. Your Wizard-generated service will have the name space http://tempuri.org. If you compile and run the service as-is you'll get a long involved message indicating you should choose a new namespace, so we add the namespace, and the WebService description as follows:
[WebService(Namespace="http://codeproject.com/webservices/",
Description="This is a demonstration WebService.")]
public class WebService1 : System.Web.Services.WebService
{
...To test the service you can right click on WebService1.asmx in the Solution Explorer in Visual Studio and choose "View in Browser". The test page is shown below,
When invoked this returns the following:
Getting the demo application to run
If you downloaded the source code with this article then you will need to create a directory 'WebServices' in your web site's root directory and extract the downloaded zip into there. You should then have:
\WebServices
\WebServices\bin
\WebServices\WebService1.asmx
...Navigating to http://localhost/WebServices/WebService1.asmx won't show you the WebService because you need to ensure that the webservice's assembly is in the application's /bin directory. You will also find that you can't load up the solution file MyService.sln. To kill two birds with one stone you will need to fire up the IIS management console, open your website's entry, right click on the WebServices folder and click Properties. Click the 'Create' button to create a new application the press OK. The /WebServices directory is now an application and so the .NET framework will load the WebService assembly from the /WebServices/bin directory, and you will be able to load and build the MyService.sln solution.
Extending the example
So we have a WebService. Not particularly exciting, but then again we haven't exactly taxed ourselves getting here. To make things slightly more interesting we'll define a method that returns an array of custom structures.
Within the MyService namespace we'll define a structure called ClientData:
public struct ClientData
{
public String Name;
public int ID;
}
and then define a new method GetClientData. Note the use of the WebMethod attribute in front of the method. This specifies that the method is accessible as a WebService method.
[WebMethod]
public ClientData[] GetClientData(int Number)
{
ClientData [] Clients = null;
if (Number > 0 && Number <= 10)
{
Clients = new ClientData[Number];
for (int i = 0; i < Number; i++)
{
Clients[i].Name = "Client " + i.ToString();
Clients[i].ID = i;
}
}
return Clients;
}
If we compile, then navigate to the the .asmx page then we are presented with a form that allows us to enter a value for the parameter. Entering a non-integer value will cause a type-error, and entering a value not in the range 1-10 will return a null array. If, however, we manage to get the input parameter correct, we'll be presented with the following XML file:
It's that easy.
Caching WebServices
Often a WebService will return the same results over multiple calls, so it makes sense to cache the information to speed things up a little. Doing so in ASP.NET is as simple as adding a CacheDuration attribute to your WebMethod:
[WebMethod(CacheDuration = 30)]
public ClientData[] GetClientData(int Number)
{The CacheDuration attribute specifies the length of time in seconds that the method should cache the results. Within that time all responses from the WebMethod will be the same.
You can also specify the CacheDuration using a constant member variable in your class:
private const int CacheTime = 30; // seconds
[WebMethod(CacheDuration = CacheTime)]
public ClientData[] GetClientData(int Number)
{Adding Descriptions to your WebMethods
In the default list of WebMethods created when you browse to the .asmx file it's nice to have a description of each method posted. The Description attribute accomplishes this.
[WebMethod(CacheDuration = 30,
Description="Returns an array of Clients.")]
public ClientData[] GetClientData(int Number)
{Your default .asmx page will then look like the following:
There are other WebMethod attributes to control buffering, session state and transaction support.
Deploying the WebService
Now that we have a WebService it would be kind of nice to allow others to use it (call me crazy, but...). Publishing your WebService on your server requires that your solution be deployed correctly. On the Build menu of Visual Studio is a "Deploy" option that, when first selected, starts a Wizard that allows you to add a Deployment project to your solution. This creates an installation package that you can run on your server which will create the necessary directories, set the correct parameters and copy over the necessary files.
This doesn't really give you an idea of what, exactly, is happening, so we'll deploy our MyService manually.
Deploying the application is done using the steps in Getting the demo application to run. We need to create a directory for our service (or use an existing directory) for our .asmx file, and we need to have the service's assembly in the application's bin/ directory. Either place the .asmx file in a subdirectory on your website and place the assembly in the /bin folder in your website's root, or place the /bin in the subdirectory containing the .asmx file and mark that directory as an application (see above).
If you choose to create a separate directory and mark it as an application then Within this directory you need to add the following files and directories:
| MyService.asmx | This file acts as the URL for your service |
| MyService.disco | The discovery document for your service |
| web.config | Configuration file for your service that overrides default web settings (optional). |
| /bin | This directory holds the assembly for your service |
| /bin/MyService.dll | The actual service asembly. |
Conclusion
Writing WebServices is extremely easy. Using the Visual Studio. NET wizards makes writing and deploying these services a point and click affair, but even if you wish to do it by hand then the steps involved are extremely simple.