Mgmt 362a Bookstore Application: Middle Tier

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31

• Mgmt 362a Bookstore Application Middle Tier
• Introducing Code-Behind Files and Databound Web
  controls

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Objectives

• In this tutorial you will learn
• Write the functionality for the middle tier,
  using Visual Basic code.
• Modify code-behind files in a Web application.
• Use databound Web controls.

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31.2 Changing the Class Name in Books.aspx.vb

• Code-behind files
• Contains the code corresponding to an ASPX page
• Written in a .NET language, such as Visual Basic

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31.2 Changing the Class Name in Books.aspx.vb
(Cont.)
Figure 31.2 Code-behind files for the
Books.aspx and BookInformation.aspx pages in the
Solution Explorer.
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31.2 Changing the Class Name in Books.aspx.vb
(Cont.)
Figure 31.3 Code-behind file for the Books.aspx.
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31.2 Changing the Class Name in Books.aspx.vb
(Cont.)

• Page class
• Defines the basic functionality for an ASPX page
• Located in the System.Web.UI namespace
• Provides properties, methods and events that are
  useful to creating Web-based applications

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31.2 Changing the Class Name in Books.aspx.vb
(Cont.)
Figure 31.4 Changing the applications class
name.
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31.2 Changing the Class Name in Books.aspx.vb
(Cont.)
Figure 31.5 Changing the Books.aspx Inherits
statement.
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31.2 Defining the Click Event Handlerfor the
Books.aspx Page

• Session items
• Used for sharing values among ASPX pages
• Key-value pair
• Associates a value with a corresponding name
  (key) which identifies the value.
• Response object
• Inherited from class Page
• Redirect method
• Takes the URL of the page to which the client
  browser redirects as an argument

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31.2 Defining the Click Event Handlerfor the
Books.aspx Page (Cont.)
Figure 31.6 informationButton_Click event
handler definition.
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31.2 Creating a Databound ListBox usingan
ObjectDataSource

• Binding data to an existing ListBox
• Black triangle in the upper-right corner
• Click Choose Data Source to open the Data Source
  Configuration Wizard

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31.2 Creating a Databound ListBox usingan
ObjectDataSource (Cont.)
Figure 31.7 Creating a databound ListBox in the
GUI.
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31.2 Creating a Databound ListBox usingan
ObjectDataSource (Cont.)
Figure 31.8 Creating a new data source.
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31.2 Creating a Databound ListBox usingan
ObjectDataSource (Cont.)
Figure 31.9 Choosing a data source type.
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31.2 Creating a Databound ListBox usingan
ObjectDataSource (Cont.)
Figure 31.10 Choosing a business object.
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31.2 Creating a Databound ListBox usingan
ObjectDataSource (Cont.)

• Define Data Methods screen
• Specifies which method of the business object
  will be used to obtain the data
• GetData method

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31.2 Creating a Databound ListBox usingan
ObjectDataSource (Cont.)
Figure 31.11 Defining data methods.
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31.2 Creating a Databound ListBox usingan
ObjectDataSource (Cont.)
Figure 31.12 Finish defining Data Source for
ListBox.
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31.3 Defining the Page_Load Event Handler forthe
BookInformation.aspx Page
Figure 31.13 BookInformation class.
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31.3 Defining the Page_Load Event Handler for the
BookInformation.aspx Page (Cont.)

• Page_Load event handler
• Invoked automatically when an ASPX page is loaded

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31.3 Defining the Page_Load Event Handler for the
BookInformation.aspx Page (Cont.)
Figure 31.14 BookInformation class.
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31.3 Defining the Page_Load Event Handler for the
BookInformation.aspx Page (Cont.)
Figure 31.15 Page_Load event handler modified
to set a parameter value and open a database
connection.
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31.3 Defining the Page_Load Event Handler for the
BookInformation.aspx Page (Cont.)
Figure 31.16 Definition of the
bookListButton_Click event handler.
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31.3 Creating a Databound DetailsView Usingan
ObjectDataSource
Figure 31.17 Select ltNew Data Sourcegt in the
Choose Data Source TextBox.
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31.3 Creating a Databound DetailsView Usingan
ObjectDataSource (Cont.)
Figure 31.18 Defining the data methods.
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31.3 Creating a Databound DetailsView Usingan
ObjectDataSource (Cont.)

• Defining data parameters
• Define Parameters dialog
• Parameter Source drop-down list
• Session field textbox

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31.3 Creating a Databound DetailsView Usingan
ObjectDataSource (Cont.)
Figure 31.19 Defining the querys parameters.
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31.3 Creating a Databound DetailsView Usingan
ObjectDataSource (Cont.)

• Specifying displayed fields
• DetailsView Tasks menu
• Click Edit Fields to display the Fields dialog
• red X Button
• Removes items from the Selected fields ListBox

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31.3 Creating a Databound DetailsView Usingan
ObjectDataSource (Cont.)
Figure 31.20 Modifying the displayed fields in
the DetailsView.
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31.3 Creating a Databound DetailsView Usingan
ObjectDataSource (Cont.)
Figure 31.21 Removing displayed fields from the
DetailsView.
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31.3 Creating a Databound DetailsView Usingan
ObjectDataSource (Cont.)
Figure 31.22 Final Fields dialog.
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Finishing the Bookstore App

• When you complete Tutorial 31 that finishes the
  Bookstore app and the assignment.
• For Assignment 12
• turn in the snapshots of the two pages correctly
  executing
• and a copy of each of the code from the two code
  behind the files (not necessary to turn in th
  HTML)