I Have XML file in my project
Here is it
  <?xml version="1.0"?>
<catalog>
   <car id="1">
      <model>Scoda Fabia</model>
      <year>2011</year>
      <producer>Folkwagen</producer>
      <price>6000</price>
      <owner>Bil Johnson</owner>
      <tel>+5810456455456</tel>
      <mileage>670000</mileage>
      <registered>USA</registered>
      <image>Fabia1.JPG</image>
   </car>
   <car id="2">
      <model>Huindai Getz</model>
      <year>2008</year>
      <producer>Huindai</producer>
      <price>5000</price>
      <owner>Dimitrious Gregorakis</owner>
      <tel>+5810456445456</tel>
      <mileage>120000</mileage>
      <registered>USA</registered>
      <image>hyundai_getz2.jpg</image>
   </car>
   <car id="3">
      <model>Huindai i108</model>
      <year>2014</year>
      <producer>Huindai</producer>
      <price>15000</price>
      <owner>Dex Dexter</owner>
      <tel>+5815556445456</tel>
      <mileage>30000</mileage>
      <registered>Canada</registered>
      <image>hyundaii108.jpg</image>
   </car>
   <car id="4">
      <model>Aveo</model>
      <year>2000</year>
      <producer>Shevrole</producer>
      <price>3500</price>
      <owner>Ivan Ivanov</owner>
      <tel>+5815556445477</tel>
      <mileage>300000</mileage>
      <registered>Mexico</registered>
      <image>aveo.jpg</image>
   </car>
</catalog>
I created a class from it, here is code for class
 [XmlRoot(ElementName = "car")]
public class Car
{
    [XmlElement(ElementName = "model")]
    public string Model { get; set; }
    [XmlElement(ElementName = "year")]
    public string Year { get; set; }
    [XmlElement(ElementName = "producer")]
    public string Producer { get; set; }
    [XmlElement(ElementName = "price")]
    public string Price { get; set; }
    [XmlElement(ElementName = "owner")]
    public string Owner { get; set; }
    [XmlElement(ElementName = "tel")]
    public string Tel { get; set; }
    [XmlElement(ElementName = "mileage")]
    public string Mileage { get; set; }
    [XmlElement(ElementName = "registered")]
    public string Registered { get; set; }
    [XmlElement(ElementName = "image")]
    public string Image { get; set; }
    [XmlAttribute(AttributeName = "id")]
    public string Id { get; set; }
}
[XmlRoot(ElementName = "catalog")]
public class Catalog
{
    [XmlElement(ElementName = "car")]
    public List<Car> Car { get; set; }
}
And Created ViewModel for it, where I defined observable collection anв define a method to fill it with data from XML
public class CarViewModel
{
    public ObservableCollection<List<Car>> car { get; set; }
    public void LoadCars()
    {
        Car = new ObservableCollection<List<Car>>();
        var path = @"xml\CarsDatabase.xml";
        using (TextReader reader = new StreamReader(path))
        {
            XmlSerializer serializer = new XmlSerializer(typeof(Catalog));
            return (Catalog)serializer.Deserialize(reader);
        }
    }
}
In method LoadCars I need to fill car observable collections with data in my file, that is inside of the project.
How I can do this correctly? Thank's for help.
UPDATE
I try to use this method
public void LoadCars()
    {
        Car = new ObservableCollection<List<Car>>();
        var path = @"xml\CarsDatabase.xml";
        using (TextReader reader = new StreamReader(path))
        {
            XmlSerializer serializer = new XmlSerializer(typeof(Catalog));
            return (Catalog)serializer.Deserialize(reader);
        }
    }
But now I have error
Severity Code Description Project File Line Suppression State Error CS0127 Since 'CarViewModel.LoadCars()' returns void, a return keyword must not be followed by an object expression DaxxTest C:\Users\nemes\Source\Repos\daxx_test\DaxxTest\DaxxTest\ViewModels\CarViewModel.cs 25 Active
 
     
     
    
>` and not, say, `List` or `ObservableCollection`?  
– fuglede Aug 12 '18 at 12:06>();": should be "car" and change ObservableCollection
– Nhan Phan Aug 12 '18 at 14:31> to ObservableCollection. in both. 
P/S: you can copy paste my answer to check it.
Cheer!