Session 4: HTML and Web Server Controls

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Session 4HTML and Web Server Controls
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Outline

• Creating Web Forms
• Using Server Controls
• HTML Server Controls
• Web Server Controls
• Writing ASP Code
• Inline Code
• Code behind pages
• Event Procedures
• Using Page Events

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What Is a Web Form?

• .aspx extension
• Page attributes
• _at_ Page directive
• Body attributes
• Form attributes

• lt_at_ Page Language"vb" gt
• lthtmlgt
• ltbodygt
• ltform id"Form1" method"post" runat"server"gt
• lt/formgt
• lt/bodygt
• lt/htmlgt

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What is a Server Control?
ltaspButton id"Button1" runat"server"
Text"Submit"/gt

• Runat"server"
• Events happen on the server
• View state saved
• Have built-in functionality
• Common object model
• All have Id and Text attributes
• Create browser-specific HTML

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Types of Server Controls

• HTML server controls
• Web server controls
• Intrinsic controls
• Validation controls
• Rich controls
• List-bound controls
• Internet Explorer Web controls

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HTML Server Controls

• Based on HTML elements
• Exist within the System.Web.UI.HtmlControls
  namespace

ltinput type"text" id"txtName" runat"server"
/gt
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Web Server Controls

• Exist within the System.Web.UI.WebControls
  namespace
• Control syntax
• HTML that is generated by the control

ltaspTextBox id"TextBox1" runat"server"gtText_to_
Display lt/aspTextBoxgt
ltinput name"TextBox1" type"text"
value"Text_to_Display" Id"TextBox1"/gt
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Selecting the Appropriate Control
Use Web Server Controls if
Use HTML Server Controls if
You prefer a Visual Basic-like programming model
You prefer an HTML-like object model
You are writing a page that might be used by a
variety of browsers
You are working with existing HTML pages and want
to quickly add ASP.NET Web page functionality
You need specific functionality such as a
calendar or ad rotator
The control will interact with client and server
script
Bandwidth is not a problem
Bandwidth is limited
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Writing ASP.NET Code Inline Code

• Code and content in the same file
• Different sections in the file for code and HTML

ltSCRIPT Language"vb" runat"server"gt Sub
btn_Click(s As Object, e As EventArgs) Handles
btn.Click ... End Sub lt/SCRIPTgt ltHTMLgt
ltaspButton id"btn" runat"server"/gt lt/HTMLgt
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Writing ASP.NET Code Code-Behind Pages

• Separation of code from content
• Developers and UI designers can work independently

Separate files
Single file
code
lttagsgt
code
lttagsgt
Form1.aspx.vb or Form1.aspx.cs
Form1.aspx
Form1.aspx
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Understanding How Code-Behind Pages Work

• Create separate files for user interface and
  interface logic
• Use _at_ Page directive to link the two files
• Pre-compile or JIT-compile

Page1.aspx.cs public class WebForm1
private void cmd1_Click()

Page1.aspx lt _at_ Page Language"c"Inherits"Proje
ct.WebForm1" Codebehind"Page1.aspx.cs" Src
"Page1.aspx.cs" gt