ASP'NET

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ASP.NET

• Another brief Overview

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ASP.NET

• Increasingly the Web and the browser interface is
  driven by the need to support applications.
• ASP.NET is not a CLR-based language.
• ASP.NET is part of the class library
• In classic ASP, VBscript was the default
  language for developing ASP pages (part of the
  reason so much VB is out there....
• VBscript is not part of the framework.
• ASP.NET applications are written in a CLR-based
  language (e.g., VB or c)

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(No Transcript)
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code-behind
Index.aspx.vb
Index.aspx
Compiled Into MSIL
IIS
Browser
Index.aspx
http
Web Controls
ADO.NET
txtLogin
authenticate user
txtPwd
User.cs
cmdLogin
dbms
Common Language Runtime
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aspx pages

• ASP.Net is not a scripted environment like
  classic ASP. All pages are compiled into classes
  that run on the CLR.
• The output of an aspx is HTML which is sent to
  the requesting browser via the web server.

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aspx pages

• In classic ASP, each page is processed
  sequentially and interpreted rather than
  compiled.
• There was really only one event in this model
  page was requested.
• ASP.Net is a fully event-driven environment.

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aspx pages

• In classic ASP vs ASP.Net
• In class demo with SQL Injection example

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aspx pages

• When a page is requested by a browser, there is a
  page_load event.
• When all processing is done, there is a
  page_unload event.
• A developer can define a click event for every
  web control on the web form.
• Life cycle of an ASPX page
• http//msdn2.microsoft.com/en-us/library/ms178472.
  aspx

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Web Controls

• Web controls are an alternative to HTML controls.
• An aspx page can have both

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Web Controls
HTML Controls
You can tell if it is a web or HTML control
because web controls have a little green arrow in
the corner.
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Code-behind

• Mixing markup tags and presentation logic syntax
  makes a page very difficult to read and maintain.
• Code-behind separates the markup tags from code
  in a separate file.
• The aspx and aspx.vb files are linked by a
  reference.

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The two files are linked
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Code-behind

• The code in a code-behind page could be written
  inline with script blocks
• ltscript runatservergtlt/scriptgt
• Or render blocks
• lt gt
• For example, in main.aspx I use a render block to
  print the content of the treeview.

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I use the Write method of the Response object to
print the contents of the variable I populated in
the code-behind page in the page_load event.
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This treeview is generated dynamically from the
database and then rendered by Response.Write
method.
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Code-behind

• Although you can still write code directly in the
  aspx page, code-behind means
• Clean separation of HTML and code
• Easier Reuse
• Simpler Maintenance
• Deployment without source code