DetailsView Control in ASP.NET - Part 4
Introduction
In Part 3 of this article series we have discussed how to display Empty
Data, that is to display the message in case of no data found. Now in this
article we will discuss how to Paging through Data in DetailsView Control.
Paging through Data in DetailsView Control
We can
use the DetailsView to page
through a set of database records by enabling the DetailsView control's AllowPaging property. There are two ways to use the paging in DetailsView Control.
Using PostBack
If we use PostBack then,
each time navigation in another page will request to server. The page given
below illustrates how we can page through the records in the PRO_LIST database
table.
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<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:DetailsView
id="dtlProducts"
DataSourceID="SqlDataSource1"
AllowPaging="true"
Runat="server" />
<br />
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:DatabaseConnectionString1 %>"
ProviderName="<%$ ConnectionStrings:DatabaseConnectionString1.ProviderName %>"
SelectCommand="SELECT [ID], [TITLE],
[COMPANY], [PRICE] FROM [PRO_LIST]">
</asp:SqlDataSource>
</div>
</form>
</body>
</html>
Using AJAX
By
default, when we page through records with the DetailsView control,
the page is posted back to the server each and every time we click a page
number. As an alternative, we can take advantage of AJAX to page through
records. When we take advantage of AJAX, only the DetailsView control
and not the entire page are updated when we navigate to a new page of records. AJAX (Asynchronous
JavaScript and XML) enables us to retrieve content from a web server without
reloading the page. AJAX works with all modern browsers. We have included the
date and time above the DetailsView Control
and we can check it while navigating to another page, it will not be updated.
The page given below illustrates how we can use AJAX with the DetailsView control.
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<div>
<b><%= DateTime.Now %></b>
<br />
<br />
<br />
</div>
<asp:DetailsView
id="dtlProducts"
DataSourceID="SqlDataSource1"
AllowPaging="true"
EnablePagingCallbacks="true"
Runat="server" />
<br />
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:DatabaseConnectionString1 %>"
ProviderName="<%$ ConnectionStrings:DatabaseConnectionString1.ProviderName %>"
SelectCommand="SELECT [ID], [TITLE],
[COMPANY], [PRICE] FROM [PRO_LIST]">
</asp:SqlDataSource>
</div>
</form>
</body>
</html>
In above code DetailsView control
included an EnablePagingCallbacks property
which has the value true. This property enables AJAX while paging with the DetailsView. We
have also included current date and time to proof it is not being PostBack. The time is not updated when we navigate to
a new page of records. The time is not updated because the entire page is not
updated. When we navigate to a new page, only the contents of the DetailsView are updated.
Note: Continue
in Next Part.
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