使用Linq从XML读取并将其添加到包含对象的列表中

Question

I'm trying to read from an XML file and add every contact to the contacts list the error i get is that can't convert List to List

writes an xml file for each contact in contacts (Works)

var path = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
    var xEle = new XElement("Contact",
        from contact in contacts
        select new XElement("Contact",
            new XAttribute("Name", contact.Name),
                new XElement("Address", contact.StreetAddress),
                new XElement("AreaCode", contact.AreaCode),
                new XElement("City", contact.City),
                new XElement("Phone", contact.Phone),
                new XElement("Email", contact.Email)
                ));
        xEle.Save(path + "\\contacts.xml");

Reads from the xml and adds it to the list (DOES NOT WORK!)

XDocument xmlDoc = XDocument.Load(path + "\\contacts.xml");
contacts = (List<Contact>)xmlDoc.Descendants("Contact");

XML File Output

<Contacts>
    <Contact Name="Nils Nilsson">
        <Address>MyStreet 17B</Address>
        <AreaCode>55555</AreaCode>
        <City>BigCity</City>
        <Phone>0705555555</Phone>
        <Email>mail@gmail.com</Email>
    </Contact>
</Contact>

Contact Class

 public class Contact
    {
        public string Name { get; set; }

        public string StreetAddress { get; set; }

        public string AreaCode { get; set; }

        public string City { get; set; }

        public string Phone { get; set; }

        public string Email { get; set; }
    }

My existing list

List<Contact> contacts = new List<Contact>();

Answer 1

As pointed out, the reason your original code doesn't work is that all queries in LINQ to XML return some form of XObject - most commonly an XAttribute or XElement . It won't map anything to Contact .

The easiest way to map your XML to your objects is to make use of built in support for XML Serialization. You class needs a couple of attributes & an extra class to map to your XML structure:

[XmlRoot("Contacts")]
public class Contacts : List<Contact>
{

}

public class Contact
{
    [XmlAttribute]
    public string Name { get; set; }

    [XmlElement("Address")]
    public string StreetAddress { get; set; }

    public string AreaCode { get; set; }

    public string City { get; set; }

    public string Phone { get; set; }

    public string Email { get; set; }
}

And then read your XML as follows:

using (var reader = XmlReader.Create(Path.Combine(path, "contacts.xml"))
{
    var serializer = new XmlSerializer(typeof(Contacts));
    var contacts = (Contacts)serializer.Deserialize(reader);
}

Note you can also use the Serialize method to create the XML in the first instance.

Answer 2

You can try something like this:

var xmlDoc = XDocument.Load(path + "\\contacts.xml");
var xElements = xmlDoc.Descendants("Contact");
var xmlSerializer = new XmlSerializer(typeof(Contact));
contacts = xElements.Select(xe => (Contact)xmlSerializer.Deserialize(xe.CreateReader())).ToList();