ASP'net Tips and Tricks

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ASP/ASP.NET Tricks and Tips
How to get Microsofts Programming Language to
work for you By Wade Tripp Park
University wtripp_at_mail.park.edu
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Disclaimer

• I am not an expert in all the details, just
  giving a general overview of how it works, and
  there are over a dozen ways how to do things,
  with half of them working.

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Who are YOU?
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History of ASP (abbreviated)

• VBScript
• Client Side
• Possible for all sorts of problems, intentional
  or not
• Required the client to have IE installed

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History of ASP (abbreviated)

• ASP
• Server Side Scripting
• Browser independent
• Required special server software
• but..
• Very much interpreted and scripting
• Created many bad programming habits

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History of ASP (abbreviated)

• ASP.NET
• Server Side Scripting
• Able to program in many languages
• Permits good programming practice
• but.
• Steep learning curve

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How ASP works

• Browser requests a web page
• Web server gets request and loads file from hard
  drive
• Web server sends the file to asp.dll to process
• Returns to the browser the processed page

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How ASP.NET works (interpreted)

• Browser requests a web page
• Web server gets request and loads the file from
  hard drive
• Web server sends the file to aspnet_isapi.dll to
  process
• Returns to the browser the processed page

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How ASP.NET works (compiled)

• Browser requests a web page
• Web server gets request and loads dll from hard
  drive
• Web server sends the file to aspnet_isapi.dll to
  process
• Returns to the browser the processed page
• The code does not have to be on the server

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Differences between ASP

• ASP
• Quick and easy to use and do
• Easy to modify and tweak
• Uses the very basics and forgiving

ASP.NET (Interpreted) Increased flexibility No
need to code everything from scratch Memory of
events Still can get confusing for large projects
ASP.NET (Compiled) Most flexible Hardest to
understand Easy to get good programming standards
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Differences between ASP

• Simple and quick ASP
• Ex Date modified, Alert Message

Repeated on several pages ASP.NET Interpreted
Ex Announcement on several web pages
Advanced Application ASP.NET Compiled Ex
Registration form
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Getting down to code

• ASP/ASP.NET handles the appearance, input/output
  of a web page
• The Code Behind focuses on the thinking and
  language
• Code Behind can happen in a web page itself and
  does not have to be in a .vb or .cs file
• Any language can use in theory, VB and C are the
  ones Microsoft has preconnected in Visual Studio,
  but almost any can be used. Java is not used for
  various legal reasons.

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Simple Displaying Stuff

• To simply display stuff ( traditionally used in
  ASP ) you use lt gt
• lt Response.Write ("Hello World") gt
• lt 2 2 gt
• ASP is forgiving, so if you miss the ( ) in
  Response.Write, it has variant type and other
  items. But if you save it as .aspx it may not
  work.

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Is .asp the same as .aspx

• No, but they are so close that most of the time
  you can just do minor changes and tweaks going
  from asp to aspx . Several things are required
  (Declaration of variables)
• The big change with CDONTS. The method for
  sending out mail was changed from ASP to ASP.NET
  IIS 5 to IIS 6 for various reasons Security
  being the main one

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QueryString vs. Forms

• There are two ways to get information.
• QueryString/Get
• Information is sent via the URL
• Form/Post
• Information sent in the page

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QueryString

• ltform method"GET"gt
• It appears in the URL
• .. /index.asp?SampletestB1Submit
• The ? Marks the end of the URL and the rest are
  variables
• Items are recoded for valid characters (make
  spaces into , turned into 26 and other items)
• Advantage jump directly to section, performing
  items

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QueryString Disadvantages

• Easily find the information via History and
  guessable test.asp?ID45
• Limited on how much information can be passed.
  Dependant on browser of 1000, 2000 characters

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Form

• What is normally used with web pages
• ltform method"POST"gt
• Better to make things go better and organized,
  less chance of being reviewed

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Actually using it

• lt
• Dim intNumber as integer
• intNumber Request.QueryString(Test)
• intNumber Request.Form(Test)
• Response.Write (intNumber)
• gt

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TIP - Polish Notation

• Based on ideas of Jan Lukasiewicz
• Standard documenting is putting type in front of
  name
• intName Integer
• strName String
• bolName Boolean values

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TIP - Polish Notation

• Also good for ASP
• txtName Textbox
• lblName Label
• panName Panel
• lstName List
• .
• It keeps you organized

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Basics of ASP.Net

• ltaspTextBox id"TextBox1" runat"server"gtlt/aspTe
  xtBoxgt
• When it is transformed by the compiler it becomes
• ltinput name"TextBox1" type"text" id"TextBox1"
  /gt
• What all happened?
• ASP.NET is transformed into HTML

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How does information get stored

• Information is stored in a hidden view, called
  the Viewstate
• It sends and organizes the information for each
  variable and items
• ltinput type"hidden" name"__VIEWSTATE"
  value"dDwxMKA0NDg0NTY3OzsLbpQGFDDxjwkOEzOioQydd7
  xkTg" /gt
• The information is stored for all server objects

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TIP Dont make everything label

• Each ASP.NET item requires resources
• Dont use labels for standard items.
• Why?
• Because it takes extra resources and time to
  download

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TIP Dont make everything label

• Each ASP.NET item requires resources
• Dont use labels for standard items.
• Why?
• Because it takes extra resources and time to
  download

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TRICKS Storing information

• Information can be handled
• Session
• Application
• Variable
• Value of ASP Object
• Hidden Field
• Passed Variable in Form

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TRICKS Database Reading

• Can connect to database via connection with SQL,
  Access, Informix, etc anything that permits ODBC
• Warning Access can cause problems with older
  web servers

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TRICKS AutoPostback

• Permits scripting to run after an item has been
  altered
• Requires Javascript

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TRICKS Validation

• Lets a user check to make sure a field is
  probably filled out
• Normally uses Javascript to validate
• There are a few ways around it (disable
  Javascript)

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TRICKS Smart Navigation

• Permits forms not to blink by using IFRAME

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TRICKS ME - ASP

• Used to find what variables and objects are used
• Remove the Me. after you go though the form