ASP .NET 2.0

1
ASP .NET 2.0
2
What is ASP .NET

• is a server-side scripting language developed by
  Microsoft
• is the next generation of ASP (Active Server
  Pages), completely new technology, not backward
  compatible to classic ASP
• is part of Microsoft .Net framework
• runs inside IIS (Internet Information Server)
• version history ASP .NET, ASP .NET 2.0, ASP .NET
  3.0
• an ASP .NET file has the extension .aspx as
  opposed to .asp as in classic ASP
• the execution and role of .aspx files is the
  same as in other server-side languages like JSP,
  PHP, etc.

3
Microsoft .Net Framework

• Microsoft .Net framework is an environment for
  building, deploying and running web-based and
  standalone enterprise applications
• it contains the following components
• programming languages C, Visual Basic .Net, J
• server technologies and client technologies ASP
  .NET,
• Windows Forms (Windows desktop solutions),
• Compact Framework (PDA/Mobile solutions)
• development environments Visual Studio .Net,
  Visual Web Developer

4
Differences between ASP .NET and ASP

• ASP .NET has a new set of programmable controls,
  XML-based components, increased performance by
  running compiled code, event-driven programming
• ASP .NET uses ADO .NET for accessing databases,
  supports full Visual Basic, not VBScript,
  supports C, C and JScript
• ASP .NET has a large set of HTML controls which
  can be controlled by scripts
• ASP .NET contains a new set of programmable
  object-oriented input controls
• all ASP.NET objects on a web page can expose
  events that can be processed by ASP.NET code

5
Running ASP .NET

• for running ASP .NET code only
• .NET Framework
• and IIS (Microsoft Internet Information Server)
• is required
• the principle of running ASP .NET code is the
  same as in running other server-side scripts like
  PHP and JSP

6
First .aspx example

• lthtmlgtltbodygtltpgtltResponse.Write(Hello .Net
  World!)gtlt/pgtlt/bodygt
• lt/htmlgt
• in classic ASP (and also available in ASP .NET),
  ASP code is inserted in html code inside the tags
  ltgt

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ASP .NET Server Controls

• in ASP .NET, ASP code is not placed entirely
  inside the html code, but instead is written in
  separate executable files
• server controls are tags understood and run by
  the server
• there are three kinds of server controls
• HTML Server Controls - Traditional HTML tags
• Web Server Controls - New ASP.NET tags
• Validation Server Controls - For input validation
  

8
HTML Server Controls

• html elements in ASP.NET files are, by default,
  treated as text. To make these elements
  programmable a runat"server" attribute to the
  html element is required. This attribute
  indicates that the element should be treated as a
  server control. The id attribute is added to
  identify the server control.
• all html server controls must be within a ltformgt
  tag with the runat"server" attribute. The
  runat"server" attribute indicates that the form
  should be processed on the server. It also
  indicates that the enclosed controls can be
  accessed by server scripts.

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HTML Server Control example

• ltscript runat"server"gt
• Sub Page_Load link1.HRef"http//www.g
  oogle.com"End Sub
• lt/scriptgt
• lthtmlgt
• ltbodygt
• ltform runat"server"gtlta id"link1"
  runat"server"gtVisit Google!lt/agtlt/formgt
• lt/bodygt
• lt/htmlgt

10
Web Server Controls

• are special tags understood by the server, but
  they do not map to any existing HTML element
• they require a runatserver attribute to work
• ltaspcontrol_name id"some_id" runat"server" /gt
• ex.
• ltscript runat"server"gtSub submit(Source As
  Object, e As EventArgs)button1.Text"You clicked
  me!"End Sub
• lt/scriptgt
• lthtmlgt
• ltbodygtltform runat"server"gt ltaspButton
  id"button1" Text"Click me!" runat"server"
  OnClick"submit"/gtlt/formgt
• lt/bodygt
• lt/htmlgt

11
Validation Server Controls

• are used to validate user input if the user
  input does not pass validation, it will display
  an error message
• each validation control performs a specific type
  of validation
• ltaspcontrol_name id"some_id" runat"server" /gt
• ex.
• lthtmlgt
• ltbodygt
• ltform runat"server"gt ltpgtEnter a number from 1
  to 100 ltaspTextBox id"tbox1" runat"server"
  /gtltbr /gtltbr /gt ltaspButton Text"Submit"
  runat"server" /gt lt/pgt ltpgt ltaspRangeValidator
  ControlToValidate"tbox1 MinimumValue"1" Maximu
  mValue"100 Type"Integer Text"The value must
  be from 1 to 100!" runat"server"
  /gt lt/pgtlt/formgt
• lt/bodygtlt/htmlgt

12
Event handlers

• ex. Page_Load event handler
• ltscript runat"server"gtSub Page_Load lbl1.Text"
  The date and time is " now()End Sub
• lt/scriptgt
• lthtmlgtltbodygtltform runat"server"gt lth3gtltasplabe
  l id"lbl1" runat"server" /gtlt/h3gtlt/formgt
• lt/bodygt
• lt/htmlgt

13
ASP .NET Web Forms

• all server controls must be defined within a
  ltformgt tag and this should have the attribute
  runatserver
• there can be only one ltform runatservergt
  control on a web page
• the form is always submitted to the page itself
  regardless of the action attribute
• the method is set to POST by default
• if not specified, name and id attribute are
  automatically assigned by ASP .NET

14
ASP .NET ViewState

• ASP .NET maintains a ViewState (containing all
  the values of the fields in the form) as a hidden
  field in the page like this
• ltinput type"hidden" name"__VIEWSTATE"value"dD
  wtNTI0ODU5MDE1OzsZBCF2ryjMpeVgUrY2eTj79HNl4Q"
  /gt
• this is useful when the frame is submitted to the
  server with an error and you have to go back and
  correct the input data on the form
• maintaining the ViewState is the default setting
  for Web forms this can be changed with the
  directive
• lt_at_ Page EnableViewState"false" gt

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aspTextBox

• ltscript runat"server"gtSub change(sender As
  Object, e As EventArgs) lbl1.Text"You changed
  text to " txt1.TextEnd Sub
• lt/scriptgt
• lthtmlgtltbodygtltform runat"server"gt Enter your
  name ltaspTextBox id"txt1" runat"server
  text"Hello World!" ontextchanged"change"
  autopostback"true"/gt ltpgtltaspLabel id"lbl1"
  runat"server" /gtlt/pgtlt/formgtlt/bodygtlt/htmlgt

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aspButton

• ltscript runat"server"gtSub submit(sender As
  Object, e As EventArgs) lbl1.Text"Your name is
  " txt1.TextEnd Sub
• lt/scriptgt
• lthtmlgtltbodygtltform runat"server"gt Enter your
  name ltaspTextBox id"txt1" runat"server"
  /gt ltaspButton OnClick"submit" Text"Submit"
  runat"server" /gt ltpgtltaspLabel id"lbl1"
  runat"server" /gtlt/pgtlt/formgt
• lt/bodygt
• lt/htmlgt

17
Data binding controls

• some controls can be bind to a datasource like a
  database, an xml file or a script
• the data binding list controls are
• aspRadioButtonList
• aspCheckBoxList
• aspDropDownList
• aspListBox
• these controls can contain ltaspListItemgt or they
  can use the items from a data source

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Binding an ArrayList to a aspRadioButtonList

• ltscript runat"server"gtSub Page_Loadif Not
  Page.IsPostBack then dim mycountriesNew
  ArrayList mycountries.Add("Norway") mycountries.
  Add("Sweden") mycountries.Add("France") mycountr
  ies.Add("Italy") mycountries.TrimToSize() mycoun
  tries.Sort() rb.DataSourcemycountries rb.DataBi
  nd()end ifend sub
• lt/scriptgt
• lthtmlgtltbodygtltform runat"server"gt ltaspRadioBut
  tonList id"rb" runat"server" /gtlt/formgt
• lt/bodygtlt/htmlgt

19
Binding an xml file to a aspRadioButtonList

• lt_at_ Import Namespace"System.Data" gt
• ltscript runat"server"gtsub Page_Load if Not
  Page.IsPostBack then dim mycountriesNew
  DataSet mycountries.ReadXml(MapPath("countries.xm
  l")) rb.DataSourcemycountries rb.DataValueField
  "value" rb.DataTextField"text" rb.DataBind()
  end ifend sub
• sub displayMessage(s as Object,e As
  EventArgs) lbl1.text"Your favorite country is
  " rb.SelectedItem.Textend sub
• lt/scriptgt
• lthtmlgt
• ltbodygtltform runat"server"gt ltaspRadioButtonList
  id"rb" runat"server" AutoPostBack"True"
  onSelectedIndexChanged"displayMessage"
  /gt ltpgtltasplabel id"lbl1" runat"server"
  /gtlt/pgtlt/formgt
• lt/bodygtlt/htmlgt

20
Creating a Database Connection using ADO .NET

• lt_at_ Import Namespace"System.Data.OleDb" gt
• ltscript runat"server"gtsub Page_Load dim
  dbconn dbconnNew OleDbConnection("ProviderMicro
  soft.Jet.OLEDB.4.0 data source"
  server.mappath("northwind.mdb")) dbconn.Open()en
  d sub
• lt/scriptgt

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Creating a Database Command

• lt_at_ Import Namespace"System.Data.OleDb" gt
• ltscript runat"server"gtsub Page_Load dim
  dbconn,sql,dbcomm dbconnNew OleDbConnection("Pro
  viderMicrosoft.Jet.OLEDB.4.0 data source"
  server.mappath("northwind.mdb")) dbconn.Open() s
  ql"SELECT FROM customers" dbcommNew
  OleDbCommand(sql,dbconn)end sub
• lt/scriptgt

22
Creating a DataReader

• lt_at_ Import Namespace"System.Data.OleDb" gt
• ltscript runat"server"gtsub Page_Load dim
  dbconn,sql,dbcomm,dbread dbconnNew
  OleDbConnection("ProviderMicrosoft.Jet.OLEDB.4.0
  data source" server.mappath("northwind.mdb")
  ) dbconn.Open() sql"SELECT FROM
  customers" dbcommNew OleDbCommand(sql,dbconn) d
  breaddbcomm.ExecuteReader()end sub
• lt/scriptgt

23
Binding a Datasource to a control

• lt_at_ Import Namespace"System.Data.OleDb"
  gtltscript runat"server"gtsub Page_Load dim
  dbconn,sql,dbcomm,dbread dbconnNew
  OleDbConnection("ProviderMicrosoft.Jet.OLEDB.4.0
  data source" server.mappath("northwind.mdb"))
  dbconn.Open() sql"SELECT FROM
  customers" dbcommNew OleDbCommand(sql,dbconn) d
  breaddbcomm.ExecuteReader() customers.DataSource
  dbread customers.DataBind() dbread.Close() dbc
  onn.Close()end sublt/scriptgtlthtmlgtltbodygt ltfor
  m runat"server"gt ltaspRepeater id"customers"
  runat"server"gt ltHeaderTemplategt lttable
  border"1" width"100"gt lttrgt ltthgtCompanynam
  elt/thgt ltthgtContactnamelt/thgt ltthgtAddresslt/thgt
  ltthgtCitylt/thgt lt/trgt lt/HeaderTemplategt lt
  ItemTemplategt lttrgt lttdgtltContainer.DataItem
  ("companyname")gtlt/tdgt lttdgtltContainer.DataIte
  m("contactname")gtlt/tdgt lttdgtltContainer.DataIt
  em("address")gtlt/tdgt lttdgtltContainer.DataItem(
  "city")gtlt/tdgt lt/trgt lt/ItemTemplategt ltFoote
  rTemplategt lt/tablegt lt/FooterTemplategt lt/asp
  Repeatergt lt/formgtlt/bodygtlt/htmlgt