BMIS 289: Spring 2002 Gonzaga University

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BMIS 289 Spring 2002Gonzaga University

• Class 14
• ASP.Net

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Tonights Agenda

• Evaluations
• ASP.Net
• Final Projects

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ASP.Net

• ASP.Net is the latest version of the ASP web
  programming technology.
• Microsoft defines ASP.Net as
• A programming framework built on the common
  language runtime that can be used on a server to
  build powerful Web applications
• So what exactly does that mean? To understand it
  better we need to clarify what the Common
  Language Runtime is.

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What is .Net?

• A couple years ago, Microsoft began introducing
  what it calls .Net (DotNet)
• DotNet is an environment for creating and running
  computer programs, including web applications.
• It consists of two major components
• Common Language Runtime (CLR)
• .Net Framework Class Library (NFCL)

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CLR

• The CLR is the core engine of DotNet. Without it,
  DotNet would not function.
• The CLR is an environment (an agent) in which
  code executes. Microsoft has designed this
  environment with these things in mind
• Memory Management - Security
• Thread Management Safety - Interoperability
• Remoting - Robustness
• Type Safety - Versioning

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NFCL

• The .Net Framework Class Library is a collection
  of object-oriented code libraries that can be
  used to create many different types of
  applications
• Command line Applications
• GUI Applications
• Web Applications
• Server/System Applications
• The NFCL saves you from writing a lot of the
  plumbing code that goes along with applications
  like these and makes it easier to focus on the
  logic of your application.

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Benefits of .Net

• As we mentioned already, it takes care of a lot
  of the dirty work associated with writing
  modern Windows programs.
• Example memory management is handled
  automatically.
• Supports a wide variety of languages
• The most popular DotNet languages are VB.Net and
  C, but other languages like C are also
  supported.
• It is not interpreted, like Java.
• It is designed to allow it to run on platforms
  other than Microsoft Windows.
• Though, as of this presentation, it is primarily
  a Windows technology.

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Drawbacks of .Net

• Because you are programming within a framework
  you are constricted (for the most part) by that
  framework.
• Example it is impossible in many situations to
  use pointers in DotNet code.
• Support for other platforms is almost
  non-existent at the moment and will take some
  time to develop
• If it does at all.
• DotNet does not entirely remove the need to
  develop and maintain program code in non-DotNet
  environments (Un-Managed Code).

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.Net As A Whole
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ASP.Net Features

• Simplicity Power
• Many common features found in web applications
  are built-in to ASP.Net and easy to use.
• Since ASP.Net is part of the .Net Framework it
  has access to most of its functionality.
• Multiple languages can be used to write ASP.Net
  pages (VB.Net, C).
• Easier and more powerful configuration
  capabilities simplify the process of setting up
  and maintaining a web application.

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ASP.Net

• In order for ASP.Net to run on a machine (server)
  it must have the .Net Runtime installed and at
  least IIS 5.0 (gtWindows 2000).
• The .Net Runtime can be downloaded from Microsoft
  and IIS 5.0 comes with Windows 2000/XP.

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ASP.Net
Test001.aspx

• A simple page in ASP.Net would look something
  like this

lt_at_ Page Language"C" gt lthtmlgt ltheadgt lt/headgt ltb
odygt lt int i for(i1 ilt10 i)
Response.Write("This is line number " i
"ltbrgt") gt lt/bodygt lt/htmlgt
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ASP.Net

• This code looks a lot like the regular ASP we are
  use to, but there is a difference.
• We are using the programming language C to write
  the ASP code. The language we are using on this
  page was specified with the _at_ Page Language
  directive.
• The syntax rules for C are more like C and
  Java.
• If we wanted to, we could use the VB.Net language
  which is much more like VBScript.

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ASP.Net

• One of the most powerful features of ASP.Net
  pages are known as server controls.
• These are objects that can be embedded within an
  ASP.Net page and referenced programmatically.
• There are many different types of server controls
  that come with ASP.Net out of the box
• Simple output labels - Calendars
• Form inputs - Data Access
• Moreover, programmers can also create their own
  custom controls.

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ASP.Net
Test002.aspx

• Here is a simple page that uses a Label server
  control

lt_at_ Page Language"C" gt lthtmlgt ltheadgt lt/headgt ltb
odygt ltpgt ltaspLabel id"Label1"
runat"server" BackColor"Gray"gt This is
text from a ASP.Net control! lt/aspLabelgt
lt/pgt ltpgt ltstronggtThis is normal HTML
Text!lt/stronggt lt/pgt lt/bodygt lt/htmlgt
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ASP.Net
Test003.asp

• Now lets consider the case where we have a form
  on a page that has two fields, a text box and a
  drop down menu.
• Suppose we wanted to retain the values a user
  entered into the form after it had already been
  posted.
• A common requirement in real-world forms that do
  a lot of validation.
• Using traditional ASP techniques we have to
  capture those inputs and write them back into the
  form, manually.

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ASP.Net
Test003.aspx

• ASP.Net has server controls that act as form
  inputs.
• This code has the same functionality as the
  previous ASP code

ltform actiontest003.aspx methodpost
runatservergt Name ltasptextbox id"FullName"
runat"server"/gtltbrgt State
ltaspdropdownlist id"State" runatservergt
ltasplistitemgtWashingtonlt/asplistitemgt
ltasplistitemgtOregonlt/asplistitemgt
ltasplistitemgtIdaholt/asplistitemgt
lt/aspdropdownlistgt ltaspbutton text"Submit"
runat"server"/gt lt/formgt
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ASP.Net

• Note that in the previous code we had four server
  controls
• ltform runatservergt
• ltasptextbox runatservergt
• ltaspdropdownlist runatservergt
• ltaspbutton runatservergt

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ASP.Net
Test004.aspx

• Many server controls have events that we can
  write code against which will be executed when
  that event occurs.
• For example, the button control has an OnClick
  event

ltscript language"C" runatservergt void
SubmitBtn_Click(Object sender, EventArgs e)
Message.Text "lth1gtHi " FullName.Text
", you live in " State.SelectedItem
"lt/h1gt" lt/scriptgt
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ASP.Net

• Note a couple of things required for the code in
  the OnClick event handler to function.
• First, we had to create an additional server
  control a label called Message
• Then, we had to indicate which function should be
  called when the button was clicked

ltasplabel id"Message" runat"server"/gt
ltaspbutton text"Submit" OnClick"SubmitBtn_Click
" runat"server"/gt
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ASP.Net
Test005.aspx

• There are also server controls that can make
  validating form input a much simpler process.
• For example, we can require that an input be
  entered by dropping in a RequiredFieldValidator
  control

ltaspRequiredFieldValidator ControlToValidate"Ful
lName" Display"Dynamic" errormessage"You
must enter your name!ltbrgt" runatserver/gt
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ASP.Net

• The RequiredFieldValidator is capable of using
  client-side script to validate the input on the
  fly.
• This functionality will only be available on
  browsers that support it.
• Validation always occurs on the server
  (downlevel)
• Browsers that support it can perform the
  validation on the client-side and catch potential
  errors quicker (uplevel)
• If a browser does not support the uplevel
  validation then the downlevel validation will
  still function.

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ASP.Net

• If we want, we can manually disable the uplevel
  validation
• Note that the Display property does not effect
  whether uplevel validation is additionally
  performed.

ltaspRequiredFieldValidator ControlToValidate"Ful
lName" EnableClientScriptFalse
Display"Dynamic" errormessage"You must
enter your name!ltbrgt" runatserver/gt
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ASP.Net
Test006.aspx

• In our OnClick event handler it would be handy to
  know if all the validators succeeded.
• We accomplish this with the Page.IsValid
  property

void SubmitBtn_Click(Object sender, EventArgs e)
if (Page.IsValid) // perform code

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ASP.Net
Test007.aspx

• If you want to summarize all form input errors
  after a submit button is clicked you can use the
  ValidationSumary control.
• This control displays all error messages
  generated by other validation controls on the
  page.

ltaspValidationSummary HeaderText"You must enter
a value in the following fields" DisplayMode"Bul
letList" EnableClientScript"true" runat"server"/
gt
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ASP.Net

• DotNet also encompasses a version of ADO known as
  ADO.Net
• ADO.Net is an object model, like the traditional
  ADO, that interfaces with many different
  providers.
• The object model looks something like this

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ASP.Net

• The process of accessing and manipulating data
  via ADO.Net works roughly like this
• A Connection object is created to link the
  ASP.Net page to the database.
• A Command object is created to issue a command to
  the database (SQL, Stored Procedure, etc).
• If all you want to do is display data then the
  results can be read into a DataReader object for
  fast, efficient display.
• If you need to process the data further the
  results are read in to a DataSet object which is
  accessed via the DataAdapter objects.

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ASP.Net
Test008.aspx

• The code in this example performs all the
  essential steps for reading from an Access
  database.
• We use the OLEDB connection, command, and reader
  objects to perform our operations.

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ASP.Net
Test009.aspx

• If you want to display records from a database in
  an HTML table then ASP.Net provides the DataGrid
  server control which generates all the HTML
  automatically.
• Note the use of the Page_Load function in this
  code. That function is an event handler that is
  automatically called each time the page is loaded.

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ASP Resources

• LearnASP.com
• www.learnasp.com
• Good for finding small, concise lessons.
• ASP 101
• www.asp101.com
• Many beginner and advanced topics here. Articles
  are larger than LearnASP
• 4 Guys..
• www.4guysfromrolla.com
• A huge ASP resource.
• MSDN
• msdn.microsoft.com
• Microsoft programming resources.

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Contact

• Yes, I stand behind what I teach so if you have
  any questions or problems in the future then just
  fire me an email
• colin_at_colinfukai.com

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THE END