Use a DataGrid control and
the
ReadXml method of the DataSet
class.
In the .aspx file, add a
DataGridcontrol for displaying the data.
In the code-behind class for the page, use the .NET language of your choice to:
Read the data from the XML file using the
ReadXmlmethod of theDataSetclass.Bind the
DataSetto theDataGridcontrol.
Figure 1-3 shows the appearance of a typical
DataGrid in a browser. Example 1-7 shows the XML used for the recipe. Examples
Example 1-8 through Example 1-10
show the .aspx and code-behind files for an
application that produces this result.
The Page_Load method
in
the code-behind, shown in Example 1-9 (VB) and Example 1-10 (C#), reads the data from the XML file using
the ReadXml method of the
DataSet class, binds the
DataSet to the DataGrid
control, and then performs the necessary cleanup.
Datasets are designed to support hierarchical data and can contain
multiple tables of data. Because of this support, when data is loaded
into the dataset, it is loaded into a Tables collection. In this
example, there is a single node in the XML called Book. The
DataSet will automatically load the XML data into
a table named Book. When binding the data to the
DataGrid, you must reference the desired table if
the DataSet contains more than one table. It is
always best to reference the table by name instead of by index
because the index value can change if the structure of the data
changes.
It’s no secret that the DataGrid
control is one of the most flexible controls provided with ASP.NET.
It outputs a complete HTML table with the bound data displayed in its
cells. When used with a rich data source, such as a data reader, a
DataTable, or a DataSet, the
DataGrid can automatically generate columns for
the data, complete with column headers (see Recipe 1.2). Unfortunately, its default appearance
and automatic behavior rarely meet the needs of a project. In this
section we discuss some ways to make changing the default appearance
and behavior a little easier, especially as it relates to displaying
XML data.
First, provide more flexibility for your graphical design team to
achieve the desired appearance by defining an
asp:DataGrid with HeaderStyle,
ItemStyle,
AlternatingItemStyle, and
Columns elements, as shown in Example 1-8.
In this example, we use the BorderColor and the
BorderWidth attributes of the
asp:DataGrid element to define the color and width
of the border around the table generated by the
DataGrid. The
AutoGenerateColumns attribute is set to
False to allow us to define the columns that will
be displayed in the grid. If this attribute is set to
True, the DataGrid will
automatically generate columns as a function of the data bound to the
grid.
The HeaderStyle element and its attributes are
used to define the appearance of the grid header. The
ItemStyle element and its attributes are used to
define the appearance of the even-numbered rows in the grid. The
AlternatingItemStyle element and its attributes
are used to define the appearance of the odd-numbered rows in the
grid. If you do not need to output the data using alternating styles,
then omit the AlternatingItemStyle element.
The Columns element is used to define the columns
in the grid, their headings, and the data fields that are bound to
each of the columns. For each column that is to appear in the grid,
an asp:BoundColumn element must be included. At a
minimum, each asp:BoundColumn element must define
the HeaderTitle attribute and the
DataField attribute. The
HeaderTitle attribute is set to the label for the
column. The DataField attribute is set to the name
of the data field in the dataset whose data is to be bound to the
column. In addition, many other attributes can be included to define
alignment, fonts, stylesheet classes, and the like as required to
achieve the desired appearance.
Example 1-7. XML data used for example
<Root>
<Book>
<BookID>1</BookID>
<Title>Access Cookbook</Title>
<ISBN>0-596-00084-7</ISBN>
<Publisher>O'Reilly</Publisher>
</Book>
<Book>
<BookID>2</BookID>
<Title>Perl Cookbook</Title>
<ISBN>1-565-92243-3</ISBN>
<Publisher>O'Reilly</Publisher>
</Book>
<Book>
<BookID>3</BookID>
<Title>Java Cookbook</Title>
<ISBN>0-596-00170-3</ISBN>
<Publisher>O'Reilly</Publisher>
</Book>
<Book>
<BookID>4</BookID>
<Title>JavaScript Application Cookbook</Title>
<ISBN>1-565-92577-7</ISBN>
<Publisher>O'Reilly</Publisher>
</Book>
<Book>
<BookID>5</BookID>
<Title>VB .Net Language in a Nutshell</Title>
<ISBN>0-596-00092-8</ISBN>
<Publisher>O'Reilly</Publisher>
</Book>
<Book>
<BookID>6</BookID>
<Title>Programming Visual Basic .Net</Title>
<ISBN>0-596-00093-6</ISBN>
<Publisher>O'Reilly</Publisher>
</Book>
<Book>
<BookID>7</BookID>
<Title>Programming C#</Title>
<ISBN>0-596-00117-7</ISBN>
<Publisher>O'Reilly</Publisher>
</Book>
<Book>
<BookID>8</BookID>
<Title>.Net Framework Essentials</Title>
<ISBN>0-596-00165-7</ISBN>
<Publisher>O'Reilly</Publisher>
</Book>
<Book>
<BookID>9</BookID>
<Title>COM and .Net Component Services</Title>
<ISBN>0-596-00103-7</ISBN>
<Publisher>O'Reilly</Publisher>
</Book>
</Root>Example 1-8. DataGrid with XML data (.aspx)
<%@ Page Language="vb" AutoEventWireup="false"
Codebehind="CH01DataGridWithXMLVB.aspx.vb"
Inherits="ASPNetCookbook.VBExamples.CH01DataGridWithXMLVB" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title>Datagrid With XML VB</title>
<link rel="stylesheet" href="css/ASPNetCookbook.css">
</head>
<body leftmargin="0" marginheight="0" marginwidth="0" topmargin="0">
<form id="frmDatagrid" method="post" runat="server">
<table width="100%" cellpadding="0" cellspacing="0" border="0">
<tr>
<td align="center">
<img src="images/ASPNETCookbookHeading_blue.gif">
</td>
</tr>
<tr>
<td class="dividerLine">
<img src="images/spacer.gif" height="6" border="0"></td>
</tr>
</table>
<table width="90%" align="center" border="0">
<tr>
<td><img src="images/spacer.gif" height="10" border="0"></td>
</tr>
<tr>
<td align="center" class="PageHeading">
DataGrid Using Data From XML (VB)</td>
</tr>
<tr>
<td><img src="images/spacer.gif" height="10" border="0"></td>
</tr>
<tr>
<td align="center">
<asp:DataGrid
id="dgBooks"
runat="server"
BorderColor="000080"
BorderWidth="2px"
AutoGenerateColumns="False"
width="100%">
<HeaderStyle
HorizontalAlign="Center"
ForeColor="#FFFFFF"
BackColor="#000080"
Font-Bold=true
CssClass="TableHeader" />
<ItemStyle
BackColor="#FFFFE0"
cssClass="TableCellNormal" />
<AlternatingItemStyle
BackColor="#FFFFFF"
cssClass="TableCellAlternating" />
<Columns>
<asp:BoundColumn HeaderText="Title" DataField="Title" />
<asp:BoundColumn HeaderText="ISBN" DataField="ISBN"
ItemStyle-HorizontalAlign="Center" />
<asp:BoundColumn HeaderText="Publisher" DataField="Publisher"
ItemStyle-HorizontalAlign="Center" />
</Columns>
</asp:DataGrid>
</td>
</tr>
</table>
</form>
</body>
</html>Example 1-9. DataGrid with XML data code-behind (.vb)
Option Explicit On
Option Strict On
'-----------------------------------------------------------------------------
'
' Module Name: CH01DataGridWithXMLVB.aspx.vb
'
' Description: This class provides the code behind for
' CH01DataGridWithXMLVB.aspx
'
'*****************************************************************************
Imports Microsoft.VisualBasic
Imports System
Imports System.Configuration
Imports System.Data
Imports System.Data.OleDb
Namespace ASPNetCookbook.VBExamples
Public Class CH01DataGridWithXMLVB
Inherits System.Web.UI.Page
'controls on form
Protected dgBooks As System.Web.UI.WebControls.DataGrid
'*************************************************************************
'
' ROUTINE: Page_Load
'
' DESCRIPTION: This routine provides the event handler for the page load
' event. It is responsible for initializing the controls
' on the page.
'
'-------------------------------------------------------------------------
Private Sub Page_Load(ByVal sender As System.Object, _
ByVal e As System.EventArgs) _
Handles MyBase.Load
Const BOOK_TABLE As String = "Book"
Dim dSet As DataSet
Dim xmlFilename As String
If (Not Page.IsPostBack) Then
Try
'get fully qualified path to the "books" xml document located
'in the xml directory
xmlFilename = Server.MapPath("xml") & "\books.xml"
'create a dataset and load the books xml document into it
dSet = New DataSet
dSet.ReadXml(xmlFilename)
'bind the dataset to the datagrid
dgBooks.DataSource = dSet.Tables(BOOK_TABLE)
dgBooks.DataBind( )
Finally
'cleanup
If (Not IsNothing(dSet)) Then
dSet.Dispose( )
End If
End Try
End If
End Sub 'Page_Load
End Class 'CH01DataGridWithXMLVB
End NamespaceExample 1-10. DataGrid with XML data code-behind (.cs)
//----------------------------------------------------------------------------
//
// Module Name: CH01DataGridWithXMLCS.aspx.cs
//
// Description: This class provides the code behind for
// CH01DataGridWithXMLCS.aspx
//
//****************************************************************************
using System;
using System.Configuration;
using System.Data;
using System.Data.OleDb;
namespace ASPNetCookbook.CSExamples
{
public class CH01DataGridWithXMLCS : System.Web.UI.Page
{
// controls on form
protected System.Web.UI.WebControls.DataGrid dgBooks;
//************************************************************************
//
// ROUTINE: Page_Load
//
// DESCRIPTION: This routine provides the event handler for the page
// load event. It is responsible for initializing the
// controls on the page.
//
//------------------------------------------------------------------------
private void Page_Load(object sender, System.EventArgs e)
{
const String BOOK_TABLE = "Book";
DataSet dSet = null;
String xmlFilename = null;
if (!Page.IsPostBack)
{
try
{
// get fully qualified path to the "books" xml document located
// in the xml directory
xmlFilename = Server.MapPath("xml") + "\\books.xml";
// create a dataset and load the books xml document into it
dSet = new DataSet( );
dSet.ReadXml(xmlFilename);
// bind the dataset to the datagrid
dgBooks.DataSource = dSet.Tables[BOOK_TABLE];
dgBooks.DataBind( );
} // try
finally
{
// cleanup
if (dSet != null)
{
dSet.Dispose( );
}
} // finally
}
} // Page_Load
} // CH01DataGridWithXMLCS
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