Read XML file into XmlDocument

XmlDocument doc = new XmlDocument();
   doc.Load("MonFichierXML.xml");

    XmlNode node = doc.SelectSingleNode("Magasin");

    XmlNodeList prop = node.SelectNodes("Items");

    foreach (XmlNode item in prop)
    {
        items Temp = new items();
        Temp.AssignInfo(item);
        lstitems.Add(Temp);
    }

If your .NET version is newer than 3.0 you can try using System.Xml.Linq.XDocument instead of XmlDocument. It is easier to process data with XDocument.

Use XmlDocument.Load() method to load XML from your file. Then use XmlDocument.InnerXml property to get XML string.

XmlDocument doc = new XmlDocument();
doc.Load("path to your file");
string xmlcontents = doc.InnerXml;