如何访问某个元素并检索数据XML

Question

My XML looks like this. I can contain n numbers of modules and n number of assignments. The assignments are nested in the modules that it contains:

<?xml version="1.0"?>
<Course name="engineering">
<Level4>
    <Module Name="electric" CreditVal="22">
        <Assignment Name="wer" Score="22" Weight="50">
        </Assignment>
        <Assignment Name="asd" Score="50" Weight="50">
        </Assignment>
    </Module>
    <Module Name="materials" CreditVal="22">
        <Assignment Name="ghj" Score="22" Weight="75>
        </Assignment>
        <Assignment Name="kl" Score="80" Weight="15">
        </Assignment>
    </Module>
</Level4>
</Course>

I am accessing the modules and assignments by the following:

XPathDocument xpd = new XPathDocument("XMLFile.xml");

//getting modules in level 4
foreach (XPathNavigator mod in xpd.CreateNavigator().Select("/Course/Level4/Module"))
{
    //Accessing module elemtns
    if (mod.HasAttributes)
    {
        Module modtoadd = new Module();
        modtoadd.Name = mod.GetAttribute("Name", "");
        Console.WriteLine("module name: " + modtoadd.Name);
        modtoadd.CreditValue = int.Parse(mod.GetAttribute("CreditVal", ""));
        Console.WriteLine("module cred: " + modtoadd.CreditValue);
        modtoadd.Assignments = new List<Assignment>();
        //Accessing assignment elements within the module element
        foreach (XPathNavigator asgn in xpd.CreateNavigator().Select("Course/Level4/Module/Assignment"))
        {
            Assignment asn = new Assignment();
            asn.Name = asgn.GetAttribute("Name", "");
            Console.WriteLine(asn.Name);
            asn.Weighting = int.Parse(asgn.GetAttribute("Weight", ""));
            Console.WriteLine(asn.Weighting);
            asn.UsersScore = int.Parse(asgn.GetAttribute("Score", ""));
            Console.WriteLine(asn.UsersScore);
            modtoadd.Assignments.Add(asn);
        };
        courseXML.Level_41.Add(modtoadd);
    }
};

What is supposed to happen: The xmlreader reads the assignment nested in the relative modules it resides in. Eg if I were to total up the module score then 'eletric' should be worth 72 and 'materials' should be worth 102.

What actually happens: After testing it I realised there is something wrong with the logic. This works fine when one module is saved but if there is more than one then ALL the assignments will be added the every module. If I were to total up the module score then materials and electric are both worth 174.

I am new to XML and reading/saveing to files. Thanks for the help :)

Answer 1

I always find Linq2Xml easier to use.

var xDoc = XDocument.Load(filename);
var res  = xDoc.Descendants("Module")
            .Select(m => new
            {
                Name = (string)m.Attribute("Name"),
                CreditVal = (int)m.Attribute("CreditVal"),

                Assignments = m.Descendants("Assignment")
                                .Select(a => new
                                {
                                    Name = (string)a.Attribute("Name"),
                                    Score = (int)a.Attribute("Score"),
                                    Weight = (int)a.Attribute("Weight")
                                })
                                .ToList()
            })
            .ToList();

Answer 2

The problem is that instead of reading the Assignment neated under the current mod , you are reading from every Assignment from the document.

//foreach (XPathNavigator asgn in xpd.CreateNavigator().Select("Course/Level4/Module/Assignment"))
foreach (XPathNavigator asgn in mod.CreateNavigator().Select("Assignment"))

However, consider using the solution provided by @Eser. It is must simpler than your approach.