ASP.NET 4 Unleased - p 37 potx

Using DataBound Controls You use DataBound controls to generate your application’s user interface for working with data.. The DataBound controls display and edit database data, XML data,

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CHAPTER 7 Creating Custom Controls with User Controls

/// <summary>

/// Execute the step’s NextStep() method

/// and move to the next step

/// </summary>

protected void btnNext_Click(object sender, EventArgs e)

{

bool success = ((IWizardStep)_currentStep).NextStep();

if (success)

{

if (StepIndex < _wizardSteps.Count - 1)

{

StepIndex++;

LoadWizardStep();

}

/// <summary>

/// Move to the previous step

/// </summary>

protected void btnPrevious_Click(object sender, EventArgs e)

{

if (StepIndex > 0)

{

StepIndex ;

LoadWizardStep();

}

</script>

html

{

font:14px Georgia,Serif;

}

fieldset

{

display:block;

width:600px;

padding:20px;

margin:10px;

}

</style>

<title>Wizard</title>

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ptg Dynamically Loading User Controls

</head>

<body>

<div>

<asp:Label

id=”lblStepNumber”

Runat=”server” />

<asp:PlaceHolder

id=”plhWizardStep”

</fieldset>

<asp:Button

id=”btnPrevious”

Text=”< Previous”

CausesValidation=”false”

OnClick=”btnPrevious_Click”

<asp:Button

id=”btnNext”

Text=”Next >”

OnClick=”btnNext_Click”

</div>

</form>

</body>

</html>

The list of wizard steps is created in the Page_Load() method The path to each wizard

step User control is added to a collection of wizard steps

The StepIndex property represents the index of the wizard step to display The value of this

property is stored in ViewState so that the value is available across multiple page requests

The current wizard step is loaded by the LoadWizardStep() method This method uses the

StepIndex to grab the path to the current wizard step Next, it uses the

Page.LoadControl() method to actually load the wizard step User control

After the LoadWizardStep() method loads the current wizard step, it calls the control’s

LoadStep() method and initializes the control

From the Library of Wow! eBook

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CHAPTER 7 Creating Custom Controls with User Controls

The page also contains a Previous and Next button When you click the Previous button,

the btnPrevious_Click() method is called and the StepIndex is reduced by one When

you click the Next button, the btnNext_Click() method is called

The btnNext_Click() method first calls the current wizard step’s NextStep() method If

this method returns the value True, one is added to the StepIndex property, and the next

wizard step is loaded Otherwise, if the NextStep() method returns false, the next wizard

step is not loaded

Summary

In this chapter, you learned how to build custom controls by creating User controls The

first section covered the basics of User controls You learned how to create a User control

and register it both in a page and in a Web configuration file You learned how to add

custom properties and events to a User control

The next topic was caching and User controls You learned how to cache the rendered

content of a User control in server memory You also learned how to share the same

cached content across multiple pages

You also explored the topic of AJAX and User controls You learned how to update

content in a User control without posting the page that contains the User control back to

the web server

Finally, you learned how to add User controls dynamically to a page You learned how to

use the <%@ Reference %> directive to cast a User control to a particular type You also

saw a series of User controls loaded dynamically to create a multipage wizard

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Overview of Data Access

IN THIS CHAPTER

Using DataBound Controls Using DataSource Controls Using Programmatic DataBinding

Understanding Templates and DataBinding Expressions Overview of SQL Server 2008 Express

Sample Database-Driven Web Application

Summary

Any web application worth writing involves data access

In this chapter, you learn how to take advantage of the rich

set of controls included in ASP.NET 4 Framework for

working with data

You learn how to take advantage of the DataBound controls

to display data in your ASP.NET pages You also learn how

to take advantage of the DataSource controls to represent

different sources of data such as databases, XML files, and

business objects

Next, you are provided with an overview of Microsoft SQL

Server 2008 Express, which is the royalty-free database

included with Visual Web Developer You learn how to

connect to this database and use it for all your data access

needs

Finally, at the end of this chapter, we build a

database-driven application, which illustrates how you can use many

of the Data controls discussed in this chapter We build an

Employee Directory application

Using DataBound Controls

You use DataBound controls to generate your application’s

user interface for working with data The DataBound

controls display and edit database data, XML data, or just

about any other type of data you can imagine

There are three main types of DataBound controls: list

controls, tabular DataBound controls, and hierarchical

DataBound

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CHAPTER 8 Overview of Data Access

Working with List Controls

List controls display simple option lists The ASP.NET 4 Framework includes the following

five list controls:

a link button, or a hyperlink

selected

be selected

the list can be selected or multiple items can be selected

selected

All five controls inherit from the same base ListControl class This means that all these

controls share a core set of properties and methods In Chapter 10, “Using List Controls,”

you can find detailed instructions on how to use each of the list controls

The examples in this chapter rely on local databases You can simply copy the database

files (the mdf files) from code examples found on the book’s website We’ll discuss the

SQL Server 2008 Express database engine that allows you to utilize these files later in the

chapter

The page in Listing 8.1 illustrates how to use all five list controls to display the same set of

database records (see Figure 8.1)

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ptg Using DataBound Controls

FIGURE 8.1 Using list controls

LISTING 8.1 ShowListControls.aspx

<%@ Page Language=”C#” %>

<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN”

“http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”>

.floater

{

float:left;

border:solid 1px black;

padding:5px;

margin:5px;

}

</style>

<title>Show List Controls</title>

</head>

<body>

<h3>BulletedList</h3>

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<asp:BulletedList

id=”BulletedList1”

DataSourceId=”srcMovies”

DataTextField=”Title”

</div>

<h3>CheckBoxList</h3>

<asp:CheckBoxList

id=”CheckBoxList1”

</div>

<h3>DropDownList</h3>

<asp:DropDownList

id=”DropDownList1”

</div>

<h3>ListBox</h3>

<asp:ListBox

id=”ListBox1”

</div>

<h3>RadioButtonList</h3>

<asp:RadioButtonList

id=”RadioButtonList1”

</div>

<asp:SqlDataSource

id=”srcMovies”

ConnectionString=”Data Source=.\SQLExpress;

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AttachDbFilename=|DataDirectory|MyDatabase.mdf;

Integrated Security=True;User Instance=True”

SelectCommand=”SELECT Title FROM Movies”

</form>

</body>

</html>

In Listing 8.1, each list control is bound to a SqlDataSource control which represents the

contents of the Movies database table For example, the BulletedList control is bound to

the DataSource control like this:

<asp:BulletedList

id=”BulletedList1”

DataSourceID=”srcMovies”

<asp:SqlDataSource

id=”srcMovies”

ConnectionString=”Data Source=.\SQLExpress;

AttachDbFilename=|DataDirectory|MyDatabase.mdf;

Integrated Security=True;User Instance=True”

SelectCommand=”SELECT Title FROM Movies”

The BulletedList control includes a DataSourceID attribute, which points to the ID of

the SqlDataSource control The DataSourceID attribute associates a DataBound control

with a DataSource control

Working with Tabular DataBound Controls

The tabular DataBound controls are the main set of controls that you use when working

with database data These controls enable you to display and, in some cases, modify data

retrieved from a database or other type of data source

Six tabular DataBound controls can be divided into two types: those that display multiple

data items at a time and those that display a single data item at a time

First, you can use any of the following controls to display a set of data items:

the GridView control to display all the records contained in the Movies database

table This control enables you to display, sort, page, select, and edit data

control, more than one data item can display in a single row

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DataList controls, a Repeater control does not automatically render an HTML table

con-trol, the ListView control supports sorting, paging, and editing database data

You can use either of the following two controls to display a single data item at a time:

use the DetailsView control to display a single record from the Movies database

table This control enables you to display, page, edit, and add data

FormView enables you to use to layout a form by using templates

NOTE

What happened to the DataGrid? The DataGrid was included in ASP.NET 1.x Framework,

but it no longer appears in the Toolbox in Visual Web Developer The DataGrid is

offi-cially deprecated You should use the GridView control instead because the GridView

is more powerful For backward-compatibility reasons, the DataGrid is included in

ASP.NET 4 Framework so that you can still use it in your pages

The page in Listing 8.2 illustrates how you can use each of the tabular DataBound controls

(see Figure 8.2)

FIGURE 8.2 Using tabular DataBound controls

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LISTING 8.2 ShowTabularDataBound.aspx

<%@ Page Language=”C#” %>

<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN”

“http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”>

.floater

{

float:left;

border:solid 1px black;

padding:5px;

margin:5px;

}

</style>

<title>Show Tabular Databound Controls</title>

</head>

<body>

<h3>GridView</h3>

<asp:GridView

id=”GridView1”

</div>

<h3>DataList</h3>

<asp:DataList

id=”DataList1”

RepeatColumns=”2”

Runat=”server”>

<%#Eval(“Title”)%>

<i>directed by</i>

<%#Eval(“Director”)%>

</ItemTemplate>

</asp:DataList>

</div>

Tiêu đề	Creating Custom Controls with User Controls
Trường học	University of XYZ
Chuyên ngành	Computer Science
Thể loại	Essay
Năm xuất bản	2025
Thành phố	City Name

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