ASP Net Basic 1

8/3/2019 ASP Net Basic 1

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Introduction to ASP.NET

Prepared By : Rajeswari Badi (190985)


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Key Learning Objectives

Introduction to Web Technology

ASP.NET Architecture

ASP.NET Web Forms and Controls

ASP.NET Programming using VS.NET

ASP.NET Security

ASP.NET Deployment

ASP.NET Application Configuration

Introduction to ASP.NET Web Services

ASP to ASP.NET Migration and Performance


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10 Reasons You Love ASP.NET!

Much simpler page development model

Clean separation of code and content

Ability to use compiled languages

Deploy and upgrade running apps with XCOPY

Support for wide range of mobile devices

Great tools support

Web farm scalable session state

Modular, well-factored architecture

Automatically detects and recovers from errors Its really, really fast!


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Introduction to Web Technology

Request Response Model

Web Server

Web Client

Presentation Layer

Scripting Client / Server side

State Less

State management Levels Page/Session/Application

Web Page Actions Get/Post


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(Or Will After This Talk!)

Pages Services

ASP.NET Architecture

HTTP Runtime


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Runtime Compilation

ASPX

File

Request

ASPX

Engine

Parse

Gend

Page

Class

Generate

Response

Request

Instantiate

Response

Code-

behind

class

Page

DLL Instantiate,

Process and

Render

Compile


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Page Life Cycle

RequestPage

Initialized

Response

Request

Response

Page Load

View State

Saved

OutputRendered

Page

Unload

ControlProperties

Updated

View State

Restored

Control

Event

Handlers


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Code

behind

ASP.NET Page Execution Cycle

IIS

ASP.NET Runtime

Instantiate controls

Parse .aspx file

Generate page class

Request .aspx file

Response

Client Server


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ASP.NET Web Forms


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What WebForm Offers

DeviceSpecific Behaviour Browser-Independence

Less Code

Server Side ControlsServer Side Controls Less Code

Drag and Drop

Validation ControlsValidation Controls Declarative Programming

User ControlsUser Controls Reusability


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Web Forms

Dramatically easier, more productive

Requires a lot less code for a given job

Enables much cleaner code organization

Server UI Controls provide encapsulation

VB-like, event-driven programming model

Functionality and rendering

Cross browser, cross device

Separation of code from content

Developers, designers can work independently Executed via CLR as native code

VB, C#, JScript or any other .NET language


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Separation of Code, Content

ASP page combines declarative tags (HTML, ASP directives, servercontrols and static text) with code

ASP.NET separates the code and tags for better manageability

Form1.asp

code

Form1.aspx

code

Form1.vb

single file separate files


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ASP.NET Server Controls(1 of 2)

Server controls encapsulate behavior

Declarative, tag with runat="server"

Generate HTML that is sent to the client

Can support multiple client types

DHTML, HTML 3.2, WML, etc.

Process input sent from client

Bind to data in Forms collection

Fire events for notifications


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ASP.NET Server Controls(2 of 2)

Allow look and feel to be customized

Template properties allow fine grained control Are stateless on the server

ViewState travels with the page or URL


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Server Controls

Server-programmable objects

Properties, method and events

Encapsulate behavior, rendering

Can render differently to support multiple browsersor other Web clients

Mobile device support should be in beta 2

Users can create server controls

And derive from existing controls!

Uses a special tag (runat=server)


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Class Hierarchy

System.Web.UI.

WebControlsListControl

ListBox

CheckBoxList

Button

Table

WebControl

System.Web.UI.Control

System.Object

TextBox

......


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How Do Server Controls Work?

When the ASP.NET page is executed:

Creates action and method attributes of form

Adds unique id and name attributes to controls Adds value attribute to controls

Adds a Hidden control to the form to save view stateinformation(see as __VIEWSTATE field)

The resulting HTML is sent down to the client


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Code Behind Pages

ASP.NET includes support for all CLR languages

VB, C#, JScript and many others

Still supports tags for backwards

compatibility Code is compiled though, not interpreted

For maximum programming power use ServerControls

Write code for them using all the features of yourfavorite language and IDE

Very VB-like get access to properties, methods andevents


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Power of Code Behind

Gives your ASP.NET applications access to the fullpower of the CLR

Compiled code

All language features

strong typing

early binding

complete language set

Structured error handling

API access

Etc, etc, etc


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Validation in ASP

Write custom code every time

Client-side code becomes interwoven with content

Server-side code works but you have to manually

propagate state between trips to the client Usually lots of tedious code snippets that take a lot

of time to get right


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Validation Controls in ASP.NET

Added to Web Form like any other server control

Controls validation for a variety of requirements

Required field

Range checking Pattern matching

You can attach more than one validation control toan input

Only works with a subset of controls


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Controls You Can Validate

SelectedItem.ValueRadioButtonList

SelectedItem.ValueDropDownList

SelectedItem.ValueListBox

TextTextBox

ValueHtmlInputFile

ValueHtmlSelect

ValueHtmlTextArea

ValueHtmlInputText

Validation PropertyControl


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Types of Validation

Required Field Input MUST be entered

Compare Input must match a pre-defined value or other control value

Range Input must be within a lower- and upper-range

Regular Expression Input must conform to a regular expression pattern

Custom Uses a custom function you create

Summary Summarizes the results of all the validation controls


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Where Does Validation Occur?

Always on the server

If your browser supports DHTML, it will also

validate on the client by default You can disable client-side validation Set the Pages ClientTarget property to "Downlevel"

It will still validate on the server

Prevents bypassing client security

Happens when you submit the page


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Displaying Validation Errors

All validation controls are checked If all pass muster the Pages IsValid property is set to

True

When input fails validation, the associatedvalidation controls Text property is displayed If the Text property is empty, it displays the

ErrorMessage property

A summary validation control displays theErrorMessage properties for all the Validationcontrols on the page

This is only displayed when the pages IsValid property isFalse


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ASP Data Binding

No real notion of binding to an HTML control Use ADO Connections, Commands and Recordsets

to retrieve data Manually iterate through Recordset results to build

an HTML Table or fill the contents of a Select Building the HTML is relatively easy; making it look

good takes longer HTML and ASP code intermingle

Recordsets are usually the only data source


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Data Binding in ASP.NET

Choices, Choices, Choices

Bind to Properties Customer:

Bind to Collections

Bind to Expressions Contact:

Bind to Method Results Outstanding Balance:

Bind to DataSets

Grid.DataSource = myDataSet.Tables(0)


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The DataBind Method

DataBind is a method on the Page object and allServer controls

Calling it once on a page will bind all child controls

Binding syntax is NOTevaluated unless/until DataBind

Binding expressions just work as long as theresult is the expected data type

You may need to coerce to the appropriate type, such as

myVal.ToString


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Complex Binding

Most applications are going to talk to a big backenddatabase like SQL Server

This is more difficult than simple binding

Going to use ADO.NET Have to deal with Inserts, Updates and Deletes

Have to manage multiple interfaces for each type ofoperation


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Complex Binding in ASP

Usually is a complicated interface

Different pages for different actions

Different code to render results, accept changes, etc.

Lots of state management that needs to occur Can quickly become a time-consuming process


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Complex Binding in ASP.NET

More complicated than simple binding, but still much easierthan ASP

Bindable server controls like DataGrid are big time savers

Supports themes out of the box to give a professional

presentation and appearance ViewState of page gives big perf benefits for maintaining

state

Supports properties and events to let you use the sameinterface for Updates and Deletes


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One Grid Does It All

DataGrid offers the ability to edit, delete and update all inthe same page

You can add special EditCommand buttons

Edit

Update Cancel

Delete

There are event handlers associated with each button putyour code there to update the database

Using a TemplateColumn in a grid gives you completecontrol over the GUI

You can put any HTML control in a cell


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ASP.NET Caching


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Caching in ASP.NET

Lots of things you can cache Cache sets of data Cache fragments of a page Cache an entire page

Lots of control over how its cached Cache based on time (keep it for x seconds) Cache based on content (keep a copy for each unique

value in this dataset) Cache based on dependencies (keep a copy until a file or

other cache item changes


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Getting Cached Items

Try retrieving item from cache Item retrieval is based on a key

MyValue = Cache(someKey)

If the return value is Nothing, create it

When you create a cache item you set the desiredlifetime and rules

Cache persists until expiration or application isrecycled

Use Cache.Insert to create item


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Creating Cached Items

Cache based on file dependency Expires when authors.xml changes

Cache.Insert("MyData", Source, NewCacheDependency(Server.MapPath("authors.xml")))

Absolute expiration

Expires in one hour Cache.Insert("MyData", Source, null, DateTime.Now.AddHours(1),

TimeSpan.Zero)

Relative expiration Expires 20 minutes after it was last used

Cache.Insert("MyData", Source, null, DateTime.MaxValue,TimeSpan.FromMinutes(20))


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Caching Support

Full page output caching

Vary by params, language, user-agent

Fragment Caching

Enables portions of pages to be cached

Extensible Cache API

Developers can cache arbitrary objects

Multiple expiration policies, file change invalidation


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Caching Directive

Add a directive to the page

Set the Duration property for how long it should beserved from cache

Set the VaryByParam to whatever GET/POSTparameters should cause a new item to be cached

Example:


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Page Fragment Caching

Allows you to mark certain regions of your page for caching Requires using Web Controls (.ascx files)

Each Web Control is a separate file Each Web Control can have its own Duration that is separate

from its Parent Just include the directive in the control Cache can be purged by duration or changing content in one of

the Web Controls child controls Uses VaryByControl parameter in OutputCache When the value of that control changes, a new entry is added to the

cache for the duration


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Thank You

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