How to access this XDocument with XML LINQ

Question

I have the following descendants:

  <ReportItem Asset="111" ESN="111" Longitude="123" Latitude="123" MessageTime="2/16/2011" MessageTimeZone="CST" MessageTimeZoneGMTOffset="-360" SpeedUnit="Mph" Speed="111" Direction="West" Address="test" Name="testing" /> 

There are multiple of these in the same XDocument but I am looping through them with the following:

IEnumerable<XElement> elements = XData.Descendants("ReportItem");

                foreach (XElement element in elements)

I am then trying to assigning these to a business objects class that contains the same names. I am wondering why this is not assigning them at all:

 foreach (XElement element in elements)
            {
                _dataPoints.AddRange((from datapoint in elements.Attributes("ReportItem")
                                      select new DataPoint()
                                      {
                                          Asset = element.Attribute("Asset").Value,
                                          ESN = element.Attribute("ESN").Value,
                                          Longitude = element.Attribute("Longitude").Value,
                                          Latitude = element.Attribute("Latitude").Value,
                                          MessageTime = element.Attribute("MessageTime").Value,
                                          MessageTimeZone = element.Attribute("MessageTimeZone").Value,
                                          MessageTimeZoneGMTOffset = element.Attribute("MessageTimeZoneGMTOffset").Value,
                                          MinutesIdle = element.Attribute("MinutesIdle").Value,
                                          Address = element.Attribute("Address").Value,
                                          Name = element.Attribute("Name").Value,
                                          TripDistance = element.Attribute("TripDistance").Value,
                                          TripDistanceUnit = element.Attribute("TripDistanceUnit").Value,
                                      }).ToList());
            }
        }

Answer 1

you are using the wrong variable - you should use the range variable but you are using the outer loop variable.

So this:

select new DataPoint()
{
   Asset = element.Attribute("Asset").Value,
   ..

should be

select new DataPoint()
{
  Asset = datapoint.Attribute("Asset").Value,
  ..

Also you do not need the outer loop in the first place, and the inner LINQ query goes over an attribute that doesn't exist - the whole thing should just be:

_dataPoints.AddRange((from datapoint in elements
                        select new DataPoint()
                        {
                            Asset = datapoint.Attribute("Asset").Value,
                            ESN = datapoint.Attribute("ESN").Value,
                            Longitude = datapoint.Attribute("Longitude").Value,
                            Latitude = datapoint.Attribute("Latitude").Value,
                            MessageTime = datapoint.Attribute("MessageTime").Value,
                            MessageTimeZone = datapoint.Attribute("MessageTimeZone").Value,
                            MessageTimeZoneGMTOffset = datapoint.Attribute("MessageTimeZoneGMTOffset").Value,
                            MinutesIdle = datapoint.Attribute("MinutesIdle").Value,
                            Address = datapoint.Attribute("Address").Value,
                            Name = datapoint.Attribute("Name").Value,
                            TripDistance = datapoint.Attribute("TripDistance").Value,
                            TripDistanceUnit = datapoint.Attribute("TripDistanceUnit").Value,
                        }).ToList());

Also note that you are using attributes that are not even defined in your XML (i.e. MinutesIdle, TripDistance, TripDistanceUnit). You either have test and handle null in this case or remove those from your DataPoint class. An example of handling null would be :

 MinutesIdle = (string)datapoint.Attribute("MinutesIdle") ?? "0",

Answer 2

What is elements.Attributes("ReportItem") in your code supposed to do?

I think what you really want is this:

_dataPoints.AddRange(XData.Descendants("ReportItem").Select(element => 
                                      select new DataPoint(){
                                          Asset = element.Attribute("Asset").Value,
                                          ESN = element.Attribute("ESN").Value,
                                          Longitude = element.Attribute("Longitude").Value,
                                          Latitude = element.Attribute("Latitude").Value,
                                          MessageTime = element.Attribute("MessageTime").Value,
                                          MessageTimeZone = element.Attribute("MessageTimeZone").Value,
                                          MessageTimeZoneGMTOffset = element.Attribute("MessageTimeZoneGMTOffset").Value,
                                          MinutesIdle = element.Attribute("MinutesIdle").Value,
                                          Address = element.Attribute("Address").Value,
                                          Name = element.Attribute("Name").Value,
                                          TripDistance = element.Attribute("TripDistance").Value,
                                          TripDistanceUnit = element.Attribute("TripDistanceUnit").Value
                                      }));