Monday, January 29, 2018

How To Read XML File Using DataTable.ReadXml()

Good afternoon friends!
In this tutorial, I will demonstrate how to read an XML file using DataTable's ReadXml() method. While reading a file using DataSet's ReadXml() method is straightforward, using the DataTable's method might cause run-time or logical bugs. One example is that when using the DataTable's ReadXml() function, the DataTable object does not contain any records or nothing at all given that fact that the method has successfully executed. To proceed, we will read an XML file below called books.xml taken from MSDN page using DataTable's ReadXml() method.
<?xml version="1.0" encoding="utf-8" ?>
<catalog>
  <book id="bk101">
    <author>Gambardella, Matthew</author>
    <title>XML Developer's Guide</title>
    <genre>Computer</genre>
    <price>44.95</price>
    <publish_date>2000-10-01</publish_date>
    <description>
      An in-depth look at creating applications
      with XML.
    </description>
  </book>
  <book id="bk102">
    <author>Ralls, Kim</author>
    <title>Midnight Rain</title>
    <genre>Fantasy</genre>
    <price>5.95</price>
    <publish_date>2000-12-16</publish_date>
    <description>
      A former architect battles corporate zombies,
      an evil sorceress, and her own childhood to become queen
      of the world.
    </description>
  </book>
  <book id="bk103">
    <author>Corets, Eva</author>
    <title>Maeve Ascendant</title>
    <genre>Fantasy</genre>
    <price>5.95</price>
    <publish_date>2000-11-17</publish_date>
    <description>
      After the collapse of a nanotechnology
      society in England, the young survivors lay the
      foundation for a new society.
    </description>
  </book>
  <book id="bk104">
    <author>Corets, Eva</author>
    <title>Oberon's Legacy</title>
    <genre>Fantasy</genre>
    <price>5.95</price>
    <publish_date>2001-03-10</publish_date>
    <description>
      In post-apocalypse England, the mysterious
      agent known only as Oberon helps to create a new life
      for the inhabitants of London. Sequel to Maeve
      Ascendant.
    </description>
  </book>
  <book id="bk105">
    <author>Corets, Eva</author>
    <title>The Sundered Grail</title>
    <genre>Fantasy</genre>
    <price>5.95</price>
    <publish_date>2001-09-10</publish_date>
    <description>
      The two daughters of Maeve, half-sisters,
      battle one another for control of England. Sequel to
      Oberon's Legacy.
    </description>
  </book>
  <book id="bk106">
    <author>Randall, Cynthia</author>
    <title>Lover Birds</title>
    <genre>Romance</genre>
    <price>4.95</price>
    <publish_date>2000-09-02</publish_date>
    <description>
      When Carla meets Paul at an ornithology
      conference, tempers fly as feathers get ruffled.
    </description>
  </book>
  <book id="bk107">
    <author>Thurman, Paula</author>
    <title>Splish Splash</title>
    <genre>Romance</genre>
    <price>4.95</price>
    <publish_date>2000-11-02</publish_date>
    <description>
      A deep sea diver finds true love twenty
      thousand leagues beneath the sea.
    </description>
  </book>
  <book id="bk108">
    <author>Knorr, Stefan</author>
    <title>Creepy Crawlies</title>
    <genre>Horror</genre>
    <price>4.95</price>
    <publish_date>2000-12-06</publish_date>
    <description>
      An anthology of horror stories about roaches,
      centipedes, scorpions  and other insects.
    </description>
  </book>
  <book id="bk109">
    <author>Kress, Peter</author>
    <title>Paradox Lost</title>
    <genre>Science Fiction</genre>
    <price>6.95</price>
    <publish_date>2000-11-02</publish_date>
    <description>
      After an inadvertant trip through a Heisenberg
      Uncertainty Device, James Salway discovers the problems
      of being quantum.
    </description>
  </book>
  <book id="bk110">
    <author>O'Brien, Tim</author>
    <title>Microsoft .NET: The Programming Bible</title>
    <genre>Computer</genre>
    <price>36.95</price>
    <publish_date>2000-12-09</publish_date>
    <description>
      Microsoft's .NET initiative is explored in
      detail in this deep programmer's reference.
    </description>
  </book>
  <book id="bk111">
    <author>O'Brien, Tim</author>
    <title>MSXML3: A Comprehensive Guide</title>
    <genre>Computer</genre>
    <price>36.95</price>
    <publish_date>2000-12-01</publish_date>
    <description>
      The Microsoft MSXML3 parser is covered in
      detail, with attention to XML DOM interfaces, XSLT processing,
      SAX and more.
    </description>
  </book>
  <book id="bk112">
    <author>Galos, Mike</author>
    <title>Visual Studio 7: A Comprehensive Guide</title>
    <genre>Computer</genre>
    <price>49.95</price>
    <publish_date>2001-04-16</publish_date>
    <description>
      Microsoft Visual Studio 7 is explored in depth,
      looking at how Visual Basic, Visual C++, C#, and ASP+ are
      integrated into a comprehensive development
      environment.
    </description>
  </book>
</catalog>
The first thing to do is to create a schema based from that file using Visual Studio. This is turn will generate a schema out from the books.xml file.
<?xml version="1.0" encoding="utf-8"?>
<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="catalog">
    <xs:complexType>
      <xs:sequence>
        <xs:element maxOccurs="unbounded" name="book">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="author" type="xs:string" />
              <xs:element name="title" type="xs:string" />
              <xs:element name="genre" type="xs:string" />
              <xs:element name="price" type="xs:decimal" />
              <xs:element name="publish_date" type="xs:date" />
              <xs:element name="description" type="xs:string" />
            </xs:sequence>
            <xs:attribute name="id" type="xs:string" use="required" />
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>
In code-behind, create a DataTable object with name "book" that will match the node name from the XML file that holds the individual records. Next is to read the XML schema first followed by the XML file.
private void FBooks_Load(object sender, EventArgs e)
{
 string exeLocation = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
 string xmlPath = Path.Combine(exeLocation, "books.xml");
 string xsdPath = Path.Combine(exeLocation, "books.xsd");
 DataTable books = new DataTable("book");
 books.ReadXmlSchema(xsdPath);
 books.ReadXml(xmlPath);
 dgvBooks.DataSource = books;
}
Output

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