Basics of ASP'NET

1
Basics of ASP.NET
2
Outline

• Introduction
• HTML Form Controls
• ASP.NET Web Controls
• Procedures and Functions
• Page Events

3
Default.html

• lthtml xmlns"http//www.w3.org/1999/xhtml" gt
• ltheadgt
• lttitlegtIndex Pagelt/titlegt
• lt/headgt
• ltbodygt
• ltform id"form1 Actioncgi" Methodget gt
• Enter name
• ltinput typetext nametextbox1 /gt
• ltinput type"submit" value"Submit" /gt
• ltinput typereset valueClear /gt
• lt/formgt
• lt/bodygt
• lt/htmlgt

4
Default.aspx

• lt_at_ Page Language"VB" AutoEventWireup"false"
  CodeFile"Default.aspx.vb" Inherits"_Default" gt
• lthtml xmlns"http//www.w3.org/1999/xhtml" gt
• lthead runat"server"gt
• lttitlegtIndex Pagelt/titlegt
• lt/headgt
• ltbodygt
• ltform id"form1" runat"server"gt
• ltdivgt
• ltaspLabel ID"Label1" runat"server"
  Text"Enter Name"gtlt/aspLabelgt
• ltaspTextBox ID"TextBox1" runat"server"
  gtlt/aspTextBoxgt
• ltaspButton ID"Button1" runat"server"
  Text"Submit" /gt
• lt/divgt
• lt/formgt
• lt/bodygt
• lt/htmlgt

5
Default.aspx.vb

• Partial Class _Default Inherits
  System.Web.UI.Page
• Protected Sub Button1_Click(ByVal sender As
  Object, ByVal e As System.EventArgs) Handles
  Button1.Click
• TextBox1.Text "Here is some sample
  text."
• End Sub
• End Class

6
Our First ASP.NET Program

• The _at_Page directive allows you to set the default
  properties for the entire page such as the
  default language
• It specifies language
• AutoEventWireup set to False
• It requires Handles clauses for pages events such
  as Load and Init.
• CodeFile the name of the code-behind file
• Inherits the name of the compiled class the page
  inherits

7
HTML Controls

• HTML controls are universal
• Other types of server controls (e.g. ASP.NET
  controls) have to be converted into HTML before
  they can be displayed on the web browser
• HTML controls lack functions compared to controls
  from other proprietary development tools
• Form control is the essential way for HTML to
  interact with users

8
ASP.NET Server Controls

• Two required attributes
• Runatserver
• ID
• ASP.NET code is never sent to the browser
• All ASP.NET server controls will be converted
  into HTML format before they are sent to the
  browser
• They provide a consistent object model and
  corresponding events and properties.

9
ltasplabelgt

• Purpose displaying text
• Attributes
• Text
• BackColor
• ForeColor

10
ltasptextboxgt

• Purpose user input
• Attributes
• textmode one line (default), multiline, or
  passwrod
• rows number of rows if textmode is set to
  multiline
• columns number of columns if textmode is set to
  multiline

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ltaspradiobuttonlistgt

• Choice of one option excludes selecting other
  options
• Example
• ltaspradiobuttonlist id"fare" runat"server"gt
• ltasplistitem id"op1" runat"server"
  value"First class" /gt
• ltasplistitem id"op2" runat"server"
  value"Coach" /gt
• lt/aspradiobuttonlistgtltbr /gt
• fairclass fare.SelectedItem.value

12
ltaspdropdownlistgt

• Selection from a list
• Example
• ltaspdropdownlist id"list1" runat"server"gt
• ltasplistitemgtMadridlt/asplistitemgt
• ltasplistitemgtOslolt/asplistitemgt
• ltasplistitemgtLisbonlt/asplistitemgt
• lt/aspdropdownlistgt

13
ltaspbuttongt

• Example
• ltaspButton ID"Button1" runat"server"
  Text"Submit" /gt

14
Procedures

• Subroutines or sub-procedures do not return
  values and cannot be used in an expression value
• Create a Subroutine
• Declared using the keyword Sub
• Exit sub statement to exit the subroutine
• End with the keywords End Sub

15
Event Procedure

• An event procedure is not executed until an event
  triggers the event procedure
• An event procedure does not return a value
• The Page_Load event procedure is triggered when
  the page is loaded into the browser

16
Page Events

• The Page object consists of a variety of methods,
  functions, and properties that can be accessed
  within the code behind the page
• The first time a page is requested by a client, a
  series of page events occurs
• The first page event is the Page_Init event which
  initializes the page control hierarchy
• The Page_Load event loads any server controls
  into memory and occurs every time the page is
  executed

17
simple.aspx

• lt_at_ Page Language"VB" AutoEventWireup"false"
  CodeFile"simple.aspx.vb" Inherits"simple" gt
• lthtml xmlns"http//www.w3.org/1999/xhtml" gt
• lthead runat"server"gt
• lttitlegtUntitled Pagelt/titlegt
• lt/headgt
• ltbodygt
• ltform id"form1" runat"server"gt
• ltdivgt
• lt/divgt
• lt/formgt
• lt/bodygt
• lt/htmlgt

18
simple.aspx.vb

• Partial Class simple Inherits System.Web.UI.Page
• Protected Sub Page_Load(ByVal sender As
  Object, ByVal e As System.EventArgs) Handles
  Me.Load
• Response.Write("This is my first line of
  ASP.NET program. ltbrgt")
• Response.Write("More to come next week.
  ltbrgt")
• End Sub
• End Class

19
More on Class

• Class is a blueprint for which objects are
  created
• Class inheritance
• It allows one class to acquire all the properties
  and methods of the parent class
• Partial class
• It allows you to split a single class into more
  than one file