Explain Garbage Collector in depth??

http://www.dotnet-tricks.com/Tutorial/netframework/0L3P131012-.Net-Garbage-Collection-in-depth.html

http://www.c-sharpcorner.com/UploadFile/skumaar_mca/garbage-collection-in-net-framework/

What are windows services? How are they differ from other .NET application? How to create Windows Service in c# ?

Microsoft Windows services, formerly known as NT services, enable you to create long-running executable applications that run in their own Windows sessions. These services can be automatically started when the computer boots, can be paused and restarted, and do not show any user interface. These features make services ideal for use on a server or whenever you need long-running functionality that does not interfere with other users who are working on the same computer.

The main difference between a service and an ordinary windows app

• Services always run (usually started when computer boots; depending on design, you can manually stop or start these)
• Services have no UI (If you want to show UI from a service, you need to do it via a separate process) and mostly do not interact directly with users
• Services run in a separate Windows session (mostly, session 0) and, therefore, are (most always) shared between all users of a computer
• Services may offer recovery actions (what to do on first, second, and subsequent failures)
• Services are a bit harder to write and especially to debug. Thus, if thinking of writing a service, please consider console app + scheduled task first windows service vs scheduled task

Refer below link :

http://www.aspdotnet-suresh.com/2011/06/creating-windows-service-in-c-or.html

http://www.csharp-examples.net/create-windows-service/

Fibonacci series

Before start the programming you need to know exactly what is the Fibonacci series, why it comes around the world??

Golden mean:

Program:

/* Fibonacci Series c language */
#include<stdio.h>
 
int main()
{
   int n, first = 0, second = 1, next, i;
 
   printf("Enter the number of terms\n");
   scanf("%d",&n);
 
   printf("First %d terms of Fibonacci series are :-\n",n);
 
   for ( i = 0 ; i < n ; i++ )
   {
      if ( i <= 1 )
         next = i;
      else
      {
         next = first + second;
         first = second;
         second = next;
      }
      printf("%d\n",next);
   }
 
   return 0;
}

Output:

IIS, Web server, Web garden, Application pool, Worker process.

http://www.codeproject.com/Articles/114910/What-is-the-difference-between-Web-Farm-and-Web-Ga

How to retrieve data from xml file, asp.net/c# ?

http://forums.asp.net/t/1801469.aspx?how+to+retrieve+data+from+xml+file+asp+net+c+

Different Types of SQL Server Functions

http://www.dotnet-tricks.com/Tutorial/sqlserver/KY3T010412-Different-Types-of-SQL-Server-Functions.html

Why do we use virtual and override?

http://stackoverflow.com/questions/7875580/why-do-we-use-virtual-and-override

http://www.codeproject.com/Articles/18734/Method-Overriding-in-C

http://programcall.com/25/csnet/method-overriding-in-csnet.aspx 

Interface in C# using an example

http://www.onlinebuff.com/article_implementing-interface-in-c-with-an-example_18.html

http://www.codeproject.com/Articles/18743/Interfaces-in-C-For-Beginners 

Passing values between Asp.Net pages

If your Asp.Net application navigates from one Web page to another Web page, you should aware of how to pass information from the source page to the destination page. You can implement various methods to pass information between Asp.Net WebPages and these methods depend on how the redirection occurs.

Using a query string is the most popular way of passing information between asp.net web pages, the other methods are Use session state , Get HTTP POST information from the source page , Create public properties in the source page and access the property values in the target page and Get control information in the target page from controls in the source page. Some of the popular methods are follows with examples.

Query String is a group of keywords that send request to the web server. These requests specified by the values following the ? (question mark). The ? (question mark)is used as a separator and it is not part of the query string.

e.g.

http://aspserver/program/path/?query_string

Passing single value

http://net-informations.com.com/page1.aspx?field1=value1

Passing multiple values

http://net-informations.com.com/page1.aspx?field1=value1&field2=value2

How to retrieve Query String values in the target page ?

string value1 = Request.QueryString["field1"];

string value2 = Request.QueryString["field2"];

When the source Asp.Net page uses the HTTP POST action redirect to the target page, you can retrieve posted values from the Form collection in the destination page.

e.g.

In the source page include a form element that contains a TextBox and a button control that post values when the form is submitted.

Set the PostBackUrl property for the control to the URL of the page to which you want to post the ASP.NET Web page

The following source code explains a Button control that is configured to post to a page named destination.aspx in the root of the Asp.Net Web site.

After the submit, we can retrieve value using Request.Form["ControlID"] at the target page.

Label1.Text = "Submitted Value: " + Request.Form["Textbox1"].ToString();

Information in the Asp.Net session state is available to all ASP.NET Web pages in the current application. It takes server memory, and the information is stored until the session expires, which can be more overhead than you want for simply passing information to the next page.

In the source page you can set the session values like the following:

Session["field1"] = "value1";

In the destination page you can read the saved session values like the following:

string field1 = (string)(Session["field1"]);

What is IsPostBack?

IsPostBack

Postback is actually sending all the information from client to web server, then web server process all those contents and returns back to the client. Most of the time ASP control will cause a post back (e. g. buttonclick) but some don't unless you tell them to do In certain events ( Listbox Index Changed,RadioButton Checked etc..) in an ASP.NET page upon which a PostBack might be needed.

IsPostBack is a property of the Asp.Net page that tells whether or not the page is on its initial load or if a user has perform a button on your web page that has caused the page to post back to itself. The value of the Page.IsPostBack property will be set to true when the page is executing after a postback, and false otherwise. We can check the value of this property based on the value and we can populate the controls on the page.

Is Postback is normally used on page _load event to detect if the web page is getting generated due to postback requested by a control on the page or if the page is getting loaded for the first time.

C# Source Code

protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { // generate form; } else { //process submitted data; } }

Notification Services in SQL Server 2005

SQL Server Notification Services is used for developing and deploying applications that generate and send notifications. Notifications are personalized messages sent to a device that subscribes to them. A subscription defines the preference of the subscriber for a specific type of event. For example, a subscriber can specify a preference to the notification application such as “Notify me when new content is added to the Web site.” The notification application in this example is the Web site. The subscriber could be the editor of the Web site or someone responsible for managing its content. The triggering event is the addition of new content. Thus, a notification will be sent to the subscriber when the triggering event occurs. The notification can be scheduled on a weekly, daily, or hourly basis. SQL Server Notification Services can be used to send a notification to a wide variety of devices, such as a subscriber’s cell phone, personal digital assistant (PDA), Windows Messenger or e-mail account.

Terminologies in Notification services

1. Subscriber is a person or application that subscribes to and receives notifications.
2. Subscription is a request for specific information to be sent to an e-mail address or a device.
3. Event is a piece of information that the subscriber may be interested in. The triggering event can be something like an increase or decrease in the price of a stock.
4. Notification is a message that contains information about the triggering event.

There are three major pieces to each notification service. Let’s briefly define and explain each.

Events

For a notification to be sent, there has to be some form of trigger. In SQL NS such a trigger is defined as an “Event”. Events can be triggered by certain actions, or they can be in time intervals, it’s up to the designer. All of the events for a notification service can be defined in the ADF for the service.

An example of an event might be that bob wants to know when his flowers were delivered to his girlfriends house, so he subscribes to the notification service that the flower shop provides. The flower shop has defined an event in their service that generates a notification when the delivery person calls in to confirm delivery. Once the event is generated, the notification is created and delivered to bob via SMS messaging.

An example of a timed event might be that a sale person from XYZ corp. needs an updated contact list each morning before he starts his day. An event is created in the notification services that creates a notification with his updated contact list and sends it to his mobile phone in the form of a smart messaging SMS message. With the press of a button, he accepts the message and his contact list is updated.

Events are created in many ways, most commonly they are pulled from SQL databases, or system logs. When the event is defined in the ADF the method for retrieving the event data is also defined.

Notifications

A notification is the actually data that is sent to a subscriber, it is basically a formatted form of the data that was retrieved when the event that goes with this notification was fired. The contents and format of the notifications that a service supports are defined in the ADF.

Microsoft has provided an XSLT content formatter to make our lives easier in respect to notifications. It allows us to apply an XSLT transform to the raw notification data. This allows us to easily prepare a notification for display to a subscriber.

Subscriptions

A subscriber is the actual real end user of the notification service, this is the guy who wants to be notified of his rising stock so he can buy his yacht. When SQL NS creates the notification service, it creates in SQL Server a database that is just for holding subscriber information. To add subscribers, the developer needs to create some sort of a subscription application, this may sound kind of like being left out cold, but that is not the case. The subscription application is left fully to the imagination of the designers of the service, but Microsoft has provided some tools that make it much easier to build. We don’t have to know the full ER model of the subscription database because we can simply utilize the managed components Microsoft has provided for us to add subscribers.

So, simply create an application for gathering the required information from a subscriber, and use the classes provided in the Microsoft.SqlServer.NotificationServices namespace. (note these are .NET classes)

Subscribers can choose the events they want to subscribe to, the format of the notifications they want, and even the media they want notifications sent to, and yes they can even choose more than one.

Of course all these features don’t program themselves, but they can easily be added to a service once you have a good handle on build ADFs. Notification services range from the very simple to the extremely complex. You can build one in a day or in a month. It all just depends on what is required for your situation.

Ref:

http://www.sql-server-performance.com/2007/notification-services-2005/