Creating Web Applications Using ASP.NET Chapter Microsoft Visual Basic.NET: Reloaded 1

Creating Web Applications Using ASP.NET

Chapter Microsoft Visual Basic .NET: Reloaded

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Objectives

• Define the terms used when talking about the Web

• Create a Web application

• Add controls to a Web form

• Start a Web application

• Use the validator controls

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Objectives (continued)

• Include a list box on a Web form

• Determine whether a postback has occurred

• Include a DataGrid control on a Web form

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Web Terminology

• Internet – world’s largest computer network• WWW (World Wide Web)

• Contains documents called web pages• Web pages are stored on Web Servers

• Web Server is a computer with software to serve up web pages in response to client requests (web browser)

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Web Terminology (continued)

• Static Web page displays information to the viewer

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Web Terminology (continued)

•HTML (Hypertext Markup Language) tags tell browser how to display information in page

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Web Terminology (continued)

• URL (Uniform Resource Locater)

• Unique address that identifies location of a web page

• URL contains 4 parts:

• http:// -- HTTP communication protocol

• Protocol is agreement between sender and receiver how data is sent and interpreted

• Host -- name of web server

• Path -- location of document on the web server

• Document name

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Web Terminology (continued)

• Dynamic Web page is interactive• It can accept information from the user and

also retrieve information for the user

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Web Terminology (continued)

• Use Web Form Designer Window to create web pages in Visual Basic .NET

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Web Terminology (continued)

• Use HTML tab to view html code automatically generated by the IDE

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Web Terminology (continued)

• .aspx file contains controls and html• .aspx.vb file contains program code

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HOW TO…

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Creating Web Applications

• Begin by starting a blank solution

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Creating Web Applications (continued)

• Add a ASP.NET Web Application project to the blank solution

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Creating Web Applications (continued)

• IDE with web form in design view

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Creating Web Applications (continued)

• Rename web pate (.aspx file) and set title property

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Adding Controls to a Web Form• Similar to adding controls to a Windows form

• Use tools contained in toolbox• Controls are not identical to Windows

counterparts• Have ID property rather than name property

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HOW TO…

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Adding Controls to a Web Form (continued)

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Adding Controls to a Web Form (continued)

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HOW TO…

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Starting a Web Application• Displays in external browser or in internal

browser built into Visual Studio .NET

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HOW TO…

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Using the Web Validator Tools

• RequiredField validator – verifies control contains data

• RangeValidator – verifies data falls within a set range of values

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HOW TO…

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Including a List Box on a Web Form

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Code for Stovall application

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Code for Stovall application (continued)

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Stovall application (continued)

• Page_Load event

• Occurs first time web form is displayed

• Also occurs when a postback action happens

• Postback refers to client requesting data from server

• IsPostBack property indicates if form is being displayed for first time or as a result of postback

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Stovall application (continued)

• Sample run of Stovall Application

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Including a DataGrid Control on a Web Form

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Including a DataGrid Control on a Web Form (continued)

• Web application for Fairview Industries connects to an Access database and displays data in datagrid

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Including a DataGrid Control on a Web Form (continued)

• Must call DataBind method to bind data to datagrid

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Customizing the Appearance of the Web DataGrid Control’s Data

• Click datagrid control and then click Auto Format link in properties list

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Customizing the Appearance of the Web DataGrid Control’s Data (continued)• Sample run of Fairview application with

Datagrid formatted using Professional 2 scheme

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Programming Example – Monthly Payment Calculator Application

• Fred Pierce has been shopping for a new car and has asked you to create an application that he can use to calculate and display his monthly car payment,

• using annual interest rates of 5%, 6%, 7%, 8%, 9%, and 10%, and

• terms of two, three, four, and five years

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TOE Chart

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User Interface

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Objects, Properties, and Settings

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Objects, Properties, and Settings (continued)

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Pseudocode

Page Load event procedure

1. if it’s the first time the Web form is displayed

fill the lstRate control with data

fill the lstTerm control with data

select the first item in each list box

end if

btnCalc Click event procedure

1. calculate the monthly payment

2. display the monthly payment in lblPayment

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Code

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Code (continued)

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Summary

• The Web consists of Web pages that are stored on Web servers

• A client uses a browser to request a Web page from a Web server

• Web pages can be either static or dynamic (interactive)

• Static Web pages contain the information to display, as well as the HTML tags that control the appearance of the information• Static Web pages are not interactive

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Summary (continued)

• Every Web page has a unique address, called a URL, that indicates its location on the Web

• A URL consists of four parts: the protocol, the name of the Web server, the path to the Web page, and the name of the Web page

• A Web server can be a remote computer or your local machine

• To make your local machine a Web server, you must install and configure Microsoft IIS (Internet Information Services)

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Summary (continued)

• A dynamic Web page requires two files: one ending with .aspx and the other with .aspx.vb• The .aspx file contains the controls and HTML

that define the Web page’s interface, and the .aspx.vb file contains program code

• You add controls to a Web form in the same way that you add controls to a Windows form

• The Web Forms tab in toolbox contains Web tools• Web tools are similar but not identical to their

Windows counterparts

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Summary (continued)

• You test a Web application using a browser

• The Web Forms tab on the toolbox contains five validator tools

• Validator tools allow you to validate user input

• You can use a Web form’s IsPostBack method to determine whether the form is being displayed for the first time