Question

have a XML file like this:

    <Datasets>
  <package id="AD">
    <iff>LRC_AD_AMSADTEXPDR</iff>
  </package>
  <package id="AL">
    <iff>LRC_AL_CLINICALTCODE</iff>
    <iff>LRC_AL_PATALGHISTRY</iff>
    <iff>LRC_AL_PATALGYCODE</iff>
    <iff>LRC_AL_PATALLERGY</iff>
    <iff>LRC_AL_PATALRGYCHEKD</iff>
  </package>
  <package id="AT">    
    <iff>LRC_AT_PATALERT</iff>
    <iff>LRC_AT_PATALRTCARE</iff>
    <iff>LRC_AT_PATALRTCODE</iff>
    <iff>LRC_AT_PATALRTDIST</iff>
    <iff>LRC_AT_PATALRTHIST</iff>
    <iff>LRC_AT_PATALRTSTAT</iff>
  </package>
  <package id="CDC">
    <iff>LRC_CDC_IFMFMCOMMENT</iff>
    <iff>LRC_CDC_IFMFORM</iff>
    <iff>LRC_CDC_IFMFRMCNTXT</iff>
    <iff>LRC_CDC_IFMFRMDATA</iff>
    <iff>LRC_CDC_IFMFRMDISDET</iff>
    <iff>LRC_CDC_IFMFRMHIMREF</iff>
    <iff>LRC_CDC_IFMFRMKEYWRD</iff>
    <iff>LRC_CDC_IFMFRMOBSRER</iff>
    <iff>LRC_CDC_IFMFRMPLCY</iff>
    <iff>LRC_CDC_IFMFRMRCPNT</iff>
    <iff>LRC_CDC_IFMFRMREF</iff>
    <iff>LRC_CDC_IFMFRMSTAHST</iff>
  </package>
    </Datasets>

I use .NET 3.5 to create an app which will have a combobox and a checkedlistbox control.
The combobox will list down all packages (like AD, AL, AT, etc.) upon selecting which the corresponding iff elements should be bound to the checkedlistbox.

I was successful in binding combobox with following code:

var pkgs = from s in xmlDoc.Descendants("package")
                       where s.HasAttributes && s.Attribute("id") != null &&
                        !String.IsNullOrEmpty(s.Attribute("id").Value)
                       select s.Attribute("id").Value;

            List<string> lst = pkgs.ToList();

            comboBox1.DataSource = lst;

When user selects the package from dropdown, in selectedIndexChange event of combobox, I want to retieve the corresponding child elements of that package and bind it to checked list box.

However, I am unable to select the child nodes (iffs) of the selected package using LINQ.

Any help is greatly appreciated!

Thanks

Answer 1

The Linq syntax to retrieve the “iffs” could be something like this:

var package = xmlDoc.Descendants("package").SingleOrDefault(s => s.HasAttributes && s.Attribute("id") != null && s.Attribute("id").Value == myPackage); // myPackage is the selected package

if (package == null)
    return null;

return package.Descendants("iff").Select(x => x.Value);

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