illustrates how to write and read XML files

   

/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy

Publisher: Sybex;
ISBN: 0782129110
*/


/*
  Example23_8.cs illustrates how to write and read XML files
*/

using System;
using System.Data;
using System.Data.SqlClient;

public class Example23_8
{

  public static void Main()
  {

    // formulate a string containing the details of the
    // database connection
    string connectionString =
      "server=localhost;database=Northwind;uid=sa;pwd=sa";

    // create a SqlConnection object to connect to the
    // database, passing the connection string to the constructor
    SqlConnection mySqlConnection =
      new SqlConnection(connectionString);

    // formulate a SELECT statement to retrieve the
    // CustomerID, CompanyName, ContactName, and Address
    // columns for the first two rows from the Customers table
    string selectString =
      "SELECT CustomerID, CompanyName, ContactName, Address " +
      "FROM Customers " +
      "WHERE CustomerID IN ('ALFKI', 'ANATR')";

    // create a SqlCommand object to hold the SELECT statement
    SqlCommand mySqlCommand = mySqlConnection.CreateCommand();

    // set the CommandText property of the SqlCommand object to
    // the SELECT string
    mySqlCommand.CommandText = selectString;

    // create a SqlDataAdapter object
    SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();

    // set the SelectCommand property of the SqlAdapter object
    // to the SqlCommand object
    mySqlDataAdapter.SelectCommand = mySqlCommand;

    // create a DataSet object to store the results of
    // the SELECT statement
    DataSet myDataSet = new DataSet();

    // open the database connection using the
    // Open() method of the SqlConnection object
    mySqlConnection.Open();

    // use the Fill() method of the SqlDataAdapter object to
    // retrieve the rows from the table, storing the rows locally
    // in a DataTable of the DataSet object
    Console.WriteLine("Retrieving rows from the Customers table");
    mySqlDataAdapter.Fill(myDataSet, "Customers");

    // get the DataTable object from the DataSet object
    DataTable myDataTable = myDataSet.Tables["Customers"];

    // use the WriteXml() method to write the DataSet out to an
    // XML file
    Console.WriteLine("Writing rows out to an XML file named " +
      "myXmlFile.xml");
    myDataSet.WriteXml("myXmlFile.xml");

    // use the WriteXmlSchema() method to write the schema of the
    // DataSet out to an XML file
    Console.WriteLine("Writing schema out to an XML file named " +
      "myXmlSchemaFile.xml");
    myDataSet.WriteXmlSchema("myXmlSchemaFile.xml");

    // use the Clear() method to clear the current rows in the DataSet
    myDataSet.Clear();

    // use the ReadXml() method to read the contents of the XML file
    // into the DataSet
    myDataSet.ReadXml("myXmlFile.xml");

    // display the columns for each row in the DataTable,
    // using a DataRow object to access each row in the DataTable
    foreach (DataRow myDataRow in myDataTable.Rows)
    {
      Console.WriteLine("CustomerID = " + myDataRow["CustomerID"]);
      Console.WriteLine("CompanyName = " + myDataRow["CompanyName"]);
      Console.WriteLine("ContactName = " + myDataRow["ContactName"]);
      Console.WriteLine("Address = " + myDataRow["Address"]);
    }

    // close the database connection using the Close() method
    // of the SqlConnection object
    mySqlConnection.Close();

  }

}