".NET" Programming Language - Features

sivaji · Jan 10, 2008, 09:14 PM

Features

1. ASP.NET Syntax and Supported Languages
2. Samples
3. Execution Process
4. Assemblies
5. State Management, Security, and Event Handling

Business Logic and Layout

* No more blending of HTML and scripting code
* Easy maintainability of your application
* Completely separate layout and processing logic
* No implementation code within HTML files
* Files for designers and files for programmers
* You can still mix HTML and scripting code if you wish

Supported Languages

* Visual Basic
* VBScript is unmanaged !
* JScript
* C#
* New component-based language
* C++
* Managed Extensions for C++
* Others: Cobol, Smalltalk, ...
* Common Language Specification (CLS)

C# Overview

* New component-oriented language from Microsoft
* Evolution of C and C++
* Introduces improvement in areas such as
* Type safety, versioning, events and garbage collection
* Provides access to APIs like .NET, COM, or Automation
* "Hello World" sample

QuickStart

* Different files with different file name extensions
* Standard ASP.NET files: .aspx or .ascx
* Web Services: .asmx
* Code (behind) files: .aspx.cs, .asmx.vb, ...
* Configuration: Web.Config
* Web applications: Global.asax and Global.asax.vb
* All of them are text files
* The easiest way to start
* Change the .asp extension to .aspx

Page Syntax

* Directives
<%@ Page language="VB" [...] %>
* Code Declaration Blocks
<script runat="server" [...]>
[ lines of code ]
</script>
* Code Render Blocks
<%
[ inline code or expression ]
%>
* HTML Control Syntax
<HTMLelement runat="server" [attribute(s)]>
</HTMLelement>
* Custom Control Syntax
* Custom server controls
<ASP:TextBox id="MyTb1" runat="server">
* Server control property
<ASP:TextBox maxlength="80" runat="server">
* Subproperty
<ASP:Label font-size="14" runat="server">
* Server control event binding
<ASP:Button OnClick="MyClick" runat="server">
* Data Binding Expression
<asp:label
text='<%# databinding expression %>'
runat="server" />
* Server-side Object Tags
<object id="id" runat="server"
identifier="idName" />
* Server-side Include Directives

* Server-side Comments
<%-- comment block --%>

ASP.NET Sample

<html>

<script language="VB" runat=server>
Sub SubmitBtn_Click(Sender As Object, E As EventArgs)
Message.Text = "Hi " & Name.Text
End Sub
</script>

<body>
<form action="thisfile.aspx" method=post runat=server>
<h3> Name: </h3>
<asp:textbox id="Name" runat=server/>
<asp:button type=submit text="LookUp"
OnClick="SubmitBtn_Click" runat=server/>
<p>
<asp:label id="Message" runat=server/>
</p>
</form>
</body>

</html>

.aspx Execution Cycle Execution process

* Compilation, when page is requested the first time
* Microsoft intermediate language (MSIL)
* Assembly language–like style
* CPU independent
* Provides a hardware abstraction layer
* MSIL is executed by the common language runtime
* Common language runtime
* Just-in-time (JIT) compiler
* Managed code

Assemblies

* Result of compiling is still a .dll or .exe file
* Multiple- or single-file assembly

Metadata

* An assembly's manifest
* A manifest contains
* List of all assembly files
* Information about versioning, shared name
* and more ...
* The information is used to
* Locate and load class types
* Lay out object instances in memory
* Resolve method invocations and field references
* Translate MSIL to native code
* Enforce security

State Management

* Application State
* What is an "application"?
* Files, pages, modules, and executable code
* One virtual directory and its subdirectories
* Application state variables
* Global information
* Implementation rules
* Use of system resources
* "Lock" and "unlock" your global information
* Beware of global variables in multithreaded environments
* Loss of state when host is "destroyed"
* No state sharing across Web farms
* Session State
* What is a session?
* Restricted to a logical application
* Context in which a user communicates with a server
* Functionality
* Request identification and classification
* Store data across multiple requests
* Session events
* Release of session data
* .NET State Server Process

Security

* Reasons for Security
* Prevent access to areas of your Web server
* Record and store secure relevant user data
* Security Configuration in Web.Config
* <authorization>, <authentication>, <trust>, ...
* Authentication, Authorization, Impersonation
* Code Access Security
* Are you the code you told me you are?
* Protect your server from bad code
* Authentication
* Validates user credentials
* Awards an authenticated identity
* Types of authentication
* Windows, integrating with IIS 5.0
* Passport, centralized services provided by Microsoft
* Forms, request attachment
* Authorization
* Determine whether request is permitted
* File and URL authorization
* Impersonation
* IIS authenticates the "user"
* A token is passed to the ASP.NET application
* ASP.NET impersonates the given token
* Access is permitted according to NTFS settings
* Code Access Security
* .NET Framework feature
* Verify the code's identity and where it comes from
* Specify operations the code is allowed to perform

Event Model

* Application-level Event Handling
* Web Forms
* Delegate Model
* Connect event sender and event receiver
* Single and multicast delegates
* Event Delegates Are Multicast
* Event Wiring
* Register event handler with event sender
* Events raised on client, but handled on server

Event Samples

* Event samples
* System.Web.UI.WebControls
Class Button, public instance event Click
* System.Web.UI
Class Page, public instance event Load
* Events in C#
ASP.NET
C#

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".NET" Programming Language - Features

sivaji