aspnet03-01.htm

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<div class="figure"><b>Figure 3-4. </b>Page output produced from an external data 
source.</div>
<p>As you can see in the following code listing, there is very little XHTML on 
the page and no scripts. All server processing is incapsulated in the two server 
controls coded on the page.</p><pre class="divcode">&lt;?xml version="1.0" encoding="UTF-8"?&gt;

&lt;!DOCTYPE html 
  PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;
	
&lt;html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"&gt;
&lt;head&gt;
  &lt;title&gt;Database-Generated Page Output&lt;/title&gt;
&lt;/head&gt;
&lt;form Runat="Server"&gt;

&lt;h3&gt;Database-Generated Page Output&lt;/h3&gt;

&lt;asp:AccessDataSource id="BookSource" Runat="Server"
  DataFile="c:\eCommerce\Databases\BooksDB.mdb"
  SelectCommand="SELECT BookID, BookTitle, BookPrice, BookQty FROM Books 
                 ORDER BY BookID"/&gt;

&lt;asp:GridView id="BookGrid" DataSourceID="BookSource" Runat="Server"/&gt;

&lt;/form&gt;
&lt;/body&gt;
&lt;/html&gt;
</pre>
<div class="listing"><b>Listing 3-4.</b> Code for page produced from an external 
data source.</div></div>
<p>Only two server controls are needed to produce page output. An <span class="code">&lt;asp:GridView&gt;</span> control, one of the information display 
controls to which external data can be bound, automatically produces a table 
display of provided information. An <span class="code">&lt;asp:AccessDateSource&gt;</span> control extracts information from 
the database. It is associated with the GridView through the latter's <span class="code">DataSourceID</span> property so that retrieved information is 
displayed in the format given by the GridView. No special styling is applied to 
the output table; however, there is a full range of layout and styling options 
that can be applied to a GridView. Although not shown in this example, various 
user input controls can be added to the page so that users can make choices 
about which information to extract and display as output.</p>
<p class="head2">Separating Web Content from Page Display</p>
<p>An advantage of maintaining Web page content in external data stores is that 
it is more likely to be the most current and most accurate information. For 
commercial Web sites especially, much of the content already resides in 
corporate databases representing the storehouses of information used to operate 
and manage the enterprise. Web pages are current and accurate to the extent they 
can draw out and display this information in a timely manner. It makes little 
sense to hard code this information on a Web page as text and XHTML when the 
information itself can change a minute or two later. Better that Web page 
information be live, extracted from these data sources the exact second it is 
requested.</p>
<p>A second advantage of keeping page content separate from its on-page display 
is that the Web page itself seldom, if ever, requires editing. As long as the 
arrangment and presentation of information is satisfactory, page coding is never 
changed while page content changes regularly, as often as the information in the 
data stores change. The page always presents the most current information with 
no involvement of the page developer and no need for a technical or clerical