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Q:5

Client-side state management

This maintains information on the client's machine using Cookies, View State, and Query Strings.

Cookies.A cookie is a small text file on the client machine either in the client's file system or memory of

client browser session. Cookies are not good for sensitive data. Moreover, Cookies can bedisabled on the browser. Thus, you can't rely on cookies for state management.

Hidden Fields- Hidden Fields are similar to a text box but does not get displayed on theUI. However you can see the value of hidden fields when you view page source in thebrowser. Using Hidden Fields, you can pass information from one page to another pagewithout the end user's knowledge, primarily for internal processing.

View StateEach page and each control on the page has View State property. This property allows automatic

retention of page and controls state between each trip to server. This means control value ismaintained between page postbacks. Viewstate is implemented using _VIEWSTATE, a hidden

form field which gets created automatically on each page. You can't transmit data to other page

using view state.

Querystring

Querystring can maintain limited state information. Data can be passed from one page to another

with the URL but you can send limited size of data with the URL. Most browsers allow a limit of255 characters on URL length.

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Server-side state managementThis kind of mechanism retains state in the server.

Application StateThe data stored in an application object can be shared by all the sessions of the application. The

application object stores data in the key value pair.

Session StateSession state stores session-specific information and the information is visible within the sessiononly. ASP.NET creates unique sessionId for each session of the application. SessionIDs are

maintained either by an HTTP cookie or a modified URL, as set in the application's

configuration settings. By default, SessionID values are stored in a cookie.

Cache- The Cache object is an instance of the System.Web.Caching.Cache class. Cache is

stored on the server side and is more scalable in nature, as ASP.NET removes objects if the

memory becomes scarce. This also makes it unreliable in some cases. Cache objects can

have expiration polices set on them and is shared across users.

Profile- Profile data is stored in the SQL Server database by default. This database

structure is preset, so if you want any custom user details to be stored, you will need to

create a custom database and write a custom provider for it. Profiles are designed to store

information permanently.

Context.Items- The HttpContext object is provided by the Page.Context property. The

HttpContext.Items collection can be used to temporarilystore data across postback. View

state and session state can be used for a similar effect, but they assume longer-term

storage. Context can be used for storing data for one request only.

Q.8

validation controls?

Validation is important part of any web application. User's input must always be validated before sending

across different layers of the application.

Validation controls are used to:

Implement presentation logic.

To validate user input data.

Data format, data type and data range is used for validation.

There are six types of validation controls in ASP.NET

1. RequiredFieldValidation Control

2. CompareValidator Control

3. RangeValidator Control

4. RegularExpressionValidator Control

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5. CustomValidator Control

6. ValidationSummary

RequiredFieldValidation Control

The RequiredFieldValidator control is simple validation control, which checks to see if the data is enteredfor the input control. You can have a RequiredFieldValidator control for each form element on which you

wish to enforce Mandatory Field rule.

CompareValidator Control

The CompareValidator control allows you to make comparison to compare data entered in an inputcontrol with a constant value or a value in a different control.

It can most commonly be used when you need to confirm password entered by the user at the

registration time. The data is always case sensitive.

RangeValidator Control

The RangeValidator Server Control is another validator control, which checks to see if a control value is

within a valid range. The attributes that are necessary to this control are: MaximumValue, MinimumValue,

and Type.

RegularExpressionValidator Control

A regular expression is a powerful pattern matching language that can be used to identify simple and

complex characters sequence that would otherwise require writing code to perform.

Using RegularExpressionValidator server control, you can check a user's input based on a pattern that you

define using a regular expression.

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Q.2

Preprocessor directives are commands that are interpreted by the compiler and affect the output or

behavior of the build process. But the C# compiler does not have a separate preprocessor, like C andC++ you cannot use these directives to create macros. Preprocessing directives are top lines in our

program that start with '#'. The '#' is followed by an identifier that is the directive name.

Classification of C# language preprocessor directives are as follows.

Conditional compilation: We can include and exclude parts of the program based on the

conditions.

#if #else

#elif #endif #define #undef

Errors , Warnings , Line & pragma: The directive #error initiates the preprocessor to rise error,

#warninglike #error directive but it prompts warning to the user and continues with the process,

#linecan be used to hide sections of code from the debugger. The #pragma directive can either

suppress or restore specific compiler warnings.

#warning

#error #line #pragma

Region: If you want to indicate a certain block of source code with a name, you can indicate it with a

name and keep the entire block between #region and #endregion. So the C# code file is neatly

organized as blocks, and that can be expanded or collapsed visually.

#region #endregion

Q.7

ASP.Net server controls are the primary controls used in ASP.Net. These controls again could be grouped into thefollowing categories:

Validation controls- these are used to validate user input and work by running client-side script

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Data source controls- these controls provides data binding to different data sources

Data view controls- these are various lists and tables, which can bind to data from data sources for display

Personalization controls- these are used for personalization of a page according to the user's preference,based on user information

Rich controls - these implements special features, for example, AdRotator control, FileUpload control,Calendar control etc.

The basic syntax for using server controls is:

However, visual studio has the following features, which helps in error free coding:

Dragging and dropping of controls in design view

IntelliSense feature that displays and auto-completes the properties

The properties window to set the property values directly

Example: Let us look at a particular server control - a tree view control. A Tree view control comes under navigation

controls. Other Navigation controls are: Menu control and SiteMapPath control.

Add a tree view control on the page. Select Edit Nodes... from the tasks. Edit each of the nodes using theTree view node editor:

Once you have created the nodes, it looks like the following in design view:

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The AutoFormat... task allows you to format the tree view:

Add a label control and a text box control on the page and name them lblmessage and txtmessage

respectively.

Write few lines of code to ensure that when a particular node is selected, the label control displays the nodetext and the text box displays all child nodes under it, if any. The code behind file should look like this:

using System;

using System.Collections;

using System.Configuration;

using System.Data;

using System.Linq; using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

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