CODEWITHSUNDEEP
c#xmllinqlinq-to-xml
Aunt Jemima
Aunt Jemima

Reputation: 23

Not Parsing XML Data Correctly with Linq to XML

SOLVED - Thanks for your help everyone!

Before I get to my code, I'd like to offer a short explanation of what it is I'm trying to accomplish. I have an XML file in the Data folder, which has 3 Elements per descendant: Month, High and Low. Each descendant is already in the appropriate order based on Month, but I need to convert the high and low strings to doubles, so that I can use them to plot points on a graph. That is the part I am unable to accomplish.

What I have so far:

    double month = 25;
    const double temp = 275;

    string path = AppDomain.CurrentDomain.BaseDirectory + "\\Data\\";
    XDocument xmlSource;

    private void btnShowAlbany_Click(object sender, RoutedEventArgs e)
    {
        try
        {
            //Brush, Polyline, PointCollection for drawing
            SolidColorBrush myBrush = new SolidColorBrush(Color.FromArgb(255, 255, 0, 0));
            Polyline myLine = new Polyline();
            myLine.Stroke = myBrush;
            myLine.StrokeThickness = 2;
            PointCollection myPoints = new PointCollection();

            double theTemp = 0;

            //Get XML data
            xmlSource = XDocument.Load(path + @"\Albany.xml");
            var myTemps = from tmp in xmlSource.Descendants("temp")
                            select new
                            {
                                Month = tmp.Element("Month").Value,
                                High = tmp.Element("High").Value,
                                Low = tmp.Element("Low").Value
                            };

            //Pull out data for points
            foreach (var x in myTemps)
            {
                double high = Convert.ToDouble(x.High);
                double low = Convert.ToDouble(x.Low);
                theTemp = (high + low) / 2;

                myPoints.Add(new Point(month, temp - theTemp));
                month += 25;
            }

            //Add points to line, add line as child of canvas
            myLine.Points = myPoints;
            albanyCanvas.Children.Add(myLine);
        }
        catch
        {
            MessageBox.Show("Error accessing data source", "Show Temps", MessageBoxButton.OK, MessageBoxImage.Error);
        }
    }

Any guidance is appreciated, thanks.

(Note: My canvas grid values begin at 25 X, 275 Y, eg. a temp of 25 in Feb would be plotted @ 50,250)

The XML file:

<?xml version="1.0" encoding="utf-8"?>
<Temps>
  <Temp>
    <Month>Jan</Month>
    <High>31</High>
    <Low>15</Low>
  </Temp>
  <Temp>
    <Month>Feb</Month>
    <High>35</High>
    <Low>17</Low>
  </Temp>
  <Temp>
    <Month>Mar</Month>
    <High>44</High>
    <Low>26</Low>
  </Temp>
  <Temp>
    <Month>Apr</Month>
    <High>58</High>
    <Low>37</Low>
  </Temp>
  <Temp>
    <Month>May</Month>
    <High>69</High>
    <Low>47</Low>
  </Temp>
  <Temp>
    <Month>Jun</Month>
    <High>78</High>
    <Low>57</Low>
  </Temp>
  <Temp>
    <Month>Jul</Month>
    <High>82</High>
    <Low>62</Low>
  </Temp>
  <Temp>
    <Month>Aug</Month>
    <High>80</High>
    <Low>60</Low>
  </Temp>
  <Temp>
    <Month>Sep</Month>
    <High>72</High>
    <Low>52</Low>
  </Temp>
  <Temp>
    <Month>Oct</Month>
    <High>60</High>
    <Low>40</Low>
  </Temp>
  <Temp>
    <Month>Nov</Month>
    <High>48</High>
    <Low>32</Low>
  </Temp>
  <Temp>
    <Month>Dec</Month>
    <High>36</High>
    <Low>21</Low>
  </Temp>
</Temps>

Upvotes: 0

Views: 225

Answers (4)

Patrick McDonald
Patrick McDonald

Reputation: 65451

Is from tmp in xmlSource.Descendants("temp") correct?

Your XML nodes are called Temp, and XML is case sensitive

Your double high = Convert.ToDouble(x.High); looks okay so long at the data in the XML is valid, for safety you might try something like

double high;
if (!double.TryParse(x.High, out high)) {
    // handle error
}

Also, as others have pointed out, try to break your code up in smaller methods, it will be more readable and more maintainable that way

Upvotes: 4

Mark W
Mark W

Reputation: 3909

2 ways.

You can do Convert.ToDbouble(string) as suggested above but an exception would be thrown if it can't parse out the number.

You can try

double d;
Double.TryParse(strToParse, out d);

Upvotes: 0

Ilia G
Ilia G

Reputation: 10221

XML is case sensitive. Fix your selector to be .Descendants("Temp")

Upvotes: 3

Chuck Savage
Chuck Savage

Reputation: 11955

Have you tried,

Convert.ToDouble(string)

Upvotes: 0

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