using System;

using System.Data;

using System.IO;

using System.Xml;

​

public class Program

{

    public static void Main()

    {

        string xml = @"<?xml version=""1.0"" encoding=""UTF-8"" standalone=""yes""?>

<DATAPACKET Version=""2.0"">

    <METADATA>

        <FIELDS>

            <FIELD attrname=""CompanyID"" fieldtype=""string"" WIDTH=""10""/>

            <FIELD attrname=""Description"" fieldtype=""string"" WIDTH=""40""/>

        </FIELDS>

        <PARAMS/>

    </METADATA>

    <ROWDATA>

        <ROW CompanyID=""CC"" Description=""Contoso""/>

    </ROWDATA>

</DATAPACKET>

";

        XmlReader reader = XmlReader.Create(new StringReader(xml));

        DataSet dataSet = new DataSet();

        dataSet.ReadXml(reader, XmlReadMode.InferTypedSchema);

        var rowTable = dataSet.Tables["ROW"];

        var newRow = rowTable.NewRow();

        newRow["CompanyID"] = "APPL";

        newRow["Description"] = "Apple";

        rowTable.Rows.Add(newRow);

        Console.WriteLine(dataSet.GetXml());

    }

}