Beginning ASP.NET 4.5 in CSharp and VB Opsylum

456 x CHAPTER 13 DISPLAYING AND UPDATING DATA
Data Source Controls
The Data category of the Toolbox contains six different data source controls that you can use to
bind data to your data-bound controls. The XmlDataSource and SiteMapDataSource controls are
used to bind hierarchical, XML-based data to these controls. You saw SiteMapDataSource at work
when you created the site map in Chapter 7.
The ObjectDataSource control enables you to connect your data-bound controls to separate objects
in your application. Instead of tying your data-aware controls directly to a database, you bind data
from a separate layer with custom objects to them. Get yourself a copy of Wrox’s Professional
ASP.NET 4.5 (ISBN 978-1-118-31182-0) if you want to find out more about the ObjectDataSource
control.
The final three data source controls are the SqlDataSource, the EntityDataSource, and the
LinqDataSource controls. The first two are discussed in this chapter and Chapter 14, respectively.
The LinqDataSource serves as a data source for LINQ to SQL, a technology similar to the ADO.
NET Entity Framework you learn more about in Chapter 14. Because Microsoft is now promoting the
Entity Framework instead of LINQ to SQL, I won’t discuss the LinqDataSource control in this book.
The QueryExtender control acts like an add-on to the LinqDataSource and EntityDataSource
controls in that it enables you to create a rich filtering interface to search for specific data without
manually writing a lot of code. You can learn more about the QueryExtender in this article:
http://bit.ly/92kMPQ.
Other Data Controls
The final control in the Toolbox is the Chart control. It was initially released as an add-on to Visual
Studio 2008 but has now been fully integrated into VS 2012. It’s designed to render chart graphics
ranging from simple bar charts to 3-D pie charts and fancy line diagrams. I won’t discuss this control
any further, but you can find a series of articles that discuss it in detail here: http://tinyurl
.com/nsnbvv.
In the next section you see how to use the SqlDataSource and the GridView to retrieve and display
data from a database. Later sections and chapters dig deeper into the other data controls.
DATA SOURCE AND DATA-BOUND CONTROLS
WORKING TOGETHER
The SqlDataSource control enables you to quickly create functional, database-driven web pages.
Without writing a whole lot of code, you can create web pages that enable you to perform all four
operations of the CRUD acronym: Create, Read, Update, and Delete data. Although its name may
seem to imply that the control can access only Microsoft’s SQL Server, that’s not the case. The control
can access other databases, such as Oracle or MySQL, as well.
Displaying and Editing Data with GridView
To give you an idea of how the SqlDataSource control works in conjunction with the data-bound
controls, the next Try It Out shows you how to create a very simple data-driven web page that