C# 4 and .NET 4

XMl Data Type ❘ 975
connection.Open();
var reader = command.ExecuteReader(CommandBehavior.CloseConnection);
while (reader.Read())
{
SqlXml xml = reader.GetSqlXml(2);
var doc = new XmlDocument();
doc.LoadXml(xml.Value);
XmlNode examNode = doc.SelectSingleNode("//Exam");
Console.WriteLine("Exam: {0}", examNode.Attributes["Number"].Value);
XmlNode titleNode = examNode.SelectSingleNode("./Title");
Console.WriteLine("Title: {0}", titleNode.InnerText);
Console.Write("Course(s): ");
foreach (XmlNode courseNode in examNode.SelectNodes("./Course"))
{
Console.Write("{0} ", courseNode.InnerText);
}
Console.WriteLine();
}
reader.Close();
c o d e s n i p p e t X m l S a m p l e s / P r o g ra m . c s
T he XmlReader and XmlDocument classes are discussed in Chapter 33, “Manipulating
XML.”
With .NET 4 there’s another option to access the XML column
from the database. You can combine LINQ to SQL and LINQ to
XML, which makes the programming code smaller.
You can use the ADO.NET Entity Framework designer by
selecting the ADO.NET Entity Data Model template from the
Data templates category. Name the fi le ExamsModel.edmx to
create a mapping for the database SqlServerSampleDB. Select the
Exams table and select the option to singularize object names.
After you create the model with the wizard, a design surface, as
shown in Figure 34 - 4, opens.
The data context class that is created by the designer has the
name ExamsEntities and defi nes a property Exams to return all
exam rows. Here a foreach statement is used to iterate through
all records. Of course you can also defi ne a LINQ query with
a where expression if not all records are required. The Exam
figure 34-4
class defi nes the properties Id , Number , and Info according to
the columns in the database table. The Info property is of type
string . With the XElement class the string can be parsed and accessed by the LINQ to XML classes from
the namespace System.Xml.Linq . Invoking the method Element() passing the name of the XML element
Exam returns an XElement object that is then used to access the values of the attribute Number and the
elements Title and Course in a much simpler way, as was done earlier with the XmlDocument class:
using System;
using System.Xml.Linq;
namespace Wrox.ProCSharp.SqlServer
{
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