© Minder Chen, 2001-2005 ASP.NET 2.0: Introduction - 1 ASP.NET 2.0 Minder Chen, Ph.D....

© Minder Chen, 2001-2005 ASP.NET 2.0: Introduction - 1

ASP.NET 2.0

Minder Chen, Ph.D.

[email protected]

.NET Framework Base Class Library

ADO.NET: Data & XMLADO.NET: Data & XML

Windows Form: Windows User Interface

Common Language Runtime

ASP.NET: Web Forms & Web Services


.NET Framework

Operating SystemOperating SystemOperating SystemOperating System

Common Language RuntimeCommon Language RuntimeCommon Language RuntimeCommon Language Runtime

Base Class LibraryBase Class LibraryBase Class LibraryBase Class Library

ADO.NET and XMLADO.NET and XMLADO.NET and XMLADO.NET and XML

ASP.NETASP.NETWeb FormsWeb Forms Web ServicesWeb Services

Mobile FormsMobile Forms

ASP.NETASP.NETWeb FormsWeb Forms Web ServicesWeb Services

Mobile FormsMobile Forms

WindowsWindowsFormsForms

WindowsWindowsFormsForms

Common Language SpecificationCommon Language SpecificationCommon Language SpecificationCommon Language Specification

VBVBVBVB C++C++C++C++ C#C#C#C# JScriptJScriptJScriptJScript J#J#J#J#V

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Create a New Web Site


Creating a New Page


Select a Web Form


Form Handling: No Web Server Control

<%@ Page Language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >

<head id="Head1" runat="server">

<title>Untitled Page</title>

</head>

<body>

<form id="form1" >

Enter your name:

<input id="Text1" name="username" type="text" />

<input id="Submit1" type="submit" value="submit" />

<% Response.Write("Hello <b>" & _

Request.Params.Get("username") & "</b>")%>

<h1>End of the active content</h1>

<%= Date.Today.ToString("MMM, dd, yyyyy") %>

</form>

</body>

</html>

Mixing HTML and Server side scripting code

Submit to the form itself (Postback) since there is no action attribute



Toolbox – Web Server Controls


Properties Window



Create an Event Procedure

• Double click on a Web Server Control• Determine the event to be associated with the control• Write appropriate code for responding to the event


Set a Breakpoint for Debugging

• Click on the sideline of the corresponding code line to set the breakpoint

• Click again to remove the breakpoint


Set as Start Page

• Your project/web site may contain many Web forms.

• When you try to run and test a specific Web page, you should set that page to be the Start page.

• Right mouse button click on the page, choose "Set As Start Page" from the pop-up menu


Running and Debugging your Web Form


Web.config file

• You need to Add a new Web.config file for the whole Web site / Web application


Web.config


Web Application Administration• Hand editing this file or use the web admin tool to configure settings for your

application. Use the Website->Asp.Net Configuration option in VWD

• A full list of settings and comments can be found in machine.config.comments

usually located in \Windows\Microsoft.Net\Framework\v2.x\Config


Running the Web page


Debugging Functions


Error List

Include all errors from Web forms in the Web site

Enter Your Name:

<asp:TextBox ID="TextBox1" runat="server" OnTextChanged="TextBox1_TextChanged">

</asp:TextBox>

Just say NO!



Add Watch• Highlight a variable, an object, or a property• Right mouse button click to select the "Add Watch" from the menu


Page Load Event• Page Load event will be executed every time you access the page.

• Web server controls' events always post back to the page itself.

• Use IsPostBack function to determine whether it is the first request of the page or a post back to the page.

ASP.NET page's <form runat="server"> tag does not have the actionaction attribute, therefore all Web server controls event will send the form variables (i.e., Web server controls' data) to the same page to be processed by corresponding server-side event-handling methods.

PostbackPostback


PostBack<script runat="server"> Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)

If IsPostBack Then LabelWelcome.Text = "Thank you, " & TextBox1.Text & _

" for using Hello World!" Else LabelWelcome.Text = "Welcome to my Hello World!" End If End Sub Protected Sub Button1_Click(…..) Label1.Text = "Hello " & TextBox1.Text End Sub

</script>


Po

stBack

Po

stBack

First R

equest F

irst Request

Page/Control Event Execution

Page_LoadPage_Load

Page_PreRenderPage_PreRenderPage_UnloadPage_Unload

Textbox1_ChangedTextbox1_Changed

Button1_ClickButton1_Click

1. 1. ChangeChange Events Events

2. 2. ActionAction Events Events

Page DLL is loaded, control hierarchy initializedPage DLL is loaded, control hierarchy initialized

Page is disposedPage is disposed

Control hierarchy (Dynamically generated HTML page) is renderedControl hierarchy (Dynamically generated HTML page) is rendered

They may be triggered They may be triggered on PostBackon PostBack


ASP.NET Pages: Part Declarative, Part Code

• Combines declarative tags (HTML, ASPX directives, server controls tags, and static text) with code in a single file or in separate files.

• Unlike ASP, good separation provided between code and tags

Form1.aspxForm1.aspx Form1.aspxForm1.aspx Form1.aspx.vbForm1.aspx.vb

single file separate files (“code-behind”)

codecode

<tags><tags>codecode<tags><tags>


Control Event Processing

• Events are: – Triggered on the client by the user– Handled in server code

• Requires a postback to the same pageRequires a postback to the same page• ViewState of controls saves page and control

properties between round trips, therefore helps restore control to its previous state. – Implemented as a hidden form field

– Disable via setting the EnableViewState attribute EnableViewState=false

– Data Binding resets control state


How Do Server Controls Work?• Declared with runat="server" Attribute

• When the ASP.NET Page is executed:– Creates action and method attributes of form– Adds unique id and name attributes to

controls (id is used by ASP.NET and name is used by HTML form controls)

– Adds value attribute to controls (to set the default value for initial display)

– Adds a Adds a hiddenhidden control to the form to control to the form to save save view stateview state information information

<asp:textbox id="TextBox1" runat="server"></asp:textbox><asp:textbox id="TextBox1" runat="server"></asp:textbox>


Generated Generated HTML Source Code on First Request of Hello2.aspx

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><HTML><HEAD>

<title>Hello2</title><meta name="GENERATOR" content="Microsoft Visual Studio.NET 7.0"><meta name="CODE_LANGUAGE" content="Visual Basic 7.0"><meta name="vs_defaultClientScript" content="JavaScript"><meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">

</HEAD><body>

<form name="Form1" method="post" action="Hello2.aspx" id="Form1">

<input type="hidden" name="__VIEWSTATE" value="dDwtMTM3NjQ2NjY2NTs7PmhdqcuyzroBSmx2I5btO60KJNMH" /><P>Enter your name: <br>

<input name="TextBox1"name="TextBox1" type="text" id="TextBox1"id="TextBox1" /> </P>

<P>

<input type="submit" name="Button1" value="Submit" id="Button1" /> </P>

<P>

<span id="Label1"></span> </P>

<span id="Label2">First Time</span> </P></form></body></HTML>


Page Generated After Submission (Postback)<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><HTML>

<HEAD><title>Hello2</title><meta name="GENERATOR" content="Microsoft Visual Studio.NET 7.0"><meta name="CODE_LANGUAGE" content="Visual Basic 7.0"><meta name="vs_defaultClientScript" content="JavaScript"><meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">

</HEAD><body>

<form name="Form1" method="post" action="Hello2.aspx" id="Form1">

<input type="hidden" name="__VIEWSTATE" value="dDwtMTM3NjQ2NjY2NTt0PDtsPGk8MT47PjtsPHQ8O2w8aTw1Pjs+O2w8dDxwPHA8bDxUZXh0Oz47bDxNaW5kZXIgQ2hlbjs+Pjs+Ozs+Oz4+Oz4+Oz5b3aOb+KbJ2SN3XL/SHoP/3gJUvg==" />

<P>Enter your name:</P><P>

<input name="TextBox1" type="text" value="Minder Chen"value="Minder Chen" id="TextBox1" /> </P>

<P><input type="submit" name="Button1" value="Submit" id="Button1" /></P>

<P> <span id="Label1">Minder Chen</span></P>

<P> <span id="Label1">Post back</span></P></form></body></HTML>


ViewState and PostBackHello2.aspx.vb

If Not IsPostBack …First Request

Response

__VIEWSTATE = "dDwt…"

<Input id="TextBox1">Minder Chen

Post back to the same page

__VIEWSTATE = "dDwt…" Textbox1.Text = "Minder Chen"

States of a page is maintained via the ViewState between the Postback

Hello2.aspx

<asp:textbox id="TextBox1" runat="server" />

__VIEWSTATE = "dDwt…"<Input id="TextBox1" value="Minder Chen" …>

ResponseDefault value


RadioButtonList.aspx runtime


Web Form Designer

RadioButtonList

Checkbox with AutoPostBack

PanelVisible = False


Set Up Properties of Web Server Controls


Define Items in RadioButtonList control


RadioButtonList.aspx<%@ Page Language="VB" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

<script runat="server"> Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) If CheckBox1.Checked Then Label1.Text = "You know ASP.NEt 2.0 <br>" Label1.Text &= "Your level of expertise is: " & RadioButtonList1.SelectedItem.Text _

& "<br>" Label1.Text &= "Your level of expertise code is: " & RadioButtonList1.SelectedValue Else Label1.Text = "You don't know ASP.NET 2.0 <br>" End If End Sub Protected Sub CheckBox1_CheckedChanged (ByVal sender As Object, ByVal e As System.EventArgs)

If CheckBox1.Checked Then Panel1.Visible = True Else Panel1.Visible = False End If End Sub Protected Sub Page_Load (ByVal sender As Object, ByVal e As System.EventArgs) Label1.Text = " " ' Reset error message End Sub</script>

Panel1.Visible = Not Panel1.Visible


Code -- Continued<html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title>RadioButtonList </title></head><body> <form id="form1" runat="server"> <div> <strong><span style="font-size: 14pt">Auto Postback + Checkbox + DadioButtonList <br /> <br /> <asp:CheckBox ID="CheckBox1" runat="server" AutoPostBack="True" Text="I know ASP.NET 2.0"

OnCheckedChanged="CheckBox1_CheckedChanged" /><br /> <br /> </span></strong> <asp:Panel ID="Panel1" runat="server" BorderStyle="Outset"

Height="136px" Visible="False" Width="256px"> <strong>Choose your level of expertise<br /> in ASP.NET 2.0 </strong> <br /> <asp:RadioButtonList ID="RadioButtonList1" runat="server" Font-Bold="True" Width="136px"> <asp:ListItem Selected="True" Value="1">Basic</asp:ListItem> <asp:ListItem Value="2">Intermediate</asp:ListItem> <asp:ListItem Value="3">Advanced</asp:ListItem> </asp:RadioButtonList> </asp:Panel> </div> <br /> <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Submit" /> <br /> <br /> <asp:Label ID="Label1" runat="server" Font-Bold="True"></asp:Label> </form></body></html>


Add.aspx <%@ Page Language="VB" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

<script runat="server"> Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) ' Label1.Text = TextBox1.Text + TextBox2.Text Dim x1, x2, result As Single x1 = CType(TextBox1.Text, Single) x2 = CType(TextBox2.Text, Single) result = x1 + x2 ' Format String Expression "c" for currency format ' Label1.Text = Format(result, "c") Label1.Text = result.ToString("C") End Sub</script><html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server“><title>Untitled Page</title> </head> <body> <form id="form1" runat="server"> <div> <strong><span style="font-size: 14pt">Add two numbers<br /> </span></strong>Number 1: <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><br /> Plus (+)<br /> Number 2: <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox><br /> <br /> <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Submit" /><br /> <br /> Answer: <asp:Label ID="Label1" runat="server"></asp:Label> </div> </form> </body> </html>


Add.aspx with Exception Handling

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) ' Label1.Text = TextBox1.Text + TextBox2.Text Dim x1, x2, result As Single Label1.Text = ""

Try x1 = CType(TextBox1.Text, Single) Catch ex As Exception Label1.Text = "Number 1 is not a number. " & ex.Message & " <br> " End Try Try x2 = CType(TextBox2.Text, Single) Catch ex As Exception Label1.Text &= “Number 2 is not a number. " & ex.Message End Try If Label1.Text <> "" Then Exit Sub End If result = x1 + x2 ' Format String Expression "c" for currency format ' Label1.Text = Format(result, "c") Label1.Text = result.ToString("C") End Sub</script>


Runtime Compilation

ASPXFile

RequestRequest

ASPXASPX

EngineEngine

ParseParse

Gen’dPageClass

GenerateGenerate

ResponseResponse

RequestRequest

InstantiateInstantiate

ResponseResponse

Code-Code-behindbehindclassclass

PagePage

ClassClass Instantiate, Instantiate, Process and Process and

RenderRender

CompileCompile

Date post:	29-Dec-2015
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