Not able to select relevant nested nodes: LINQ

Question

My sample XML is something like this:

<?xml version="1.0" encoding="utf-8"?>
<Root>
  <RoleSecurity Name="A" Workflowstatus ="B">
    <Accountgroup Name = "Group1">
      <Attribute ID="12345" Name="Sample1"/>
      <Attribute ID="12445" Name="Sample2"/>
    </Accountgroup>
    <Accountgroup Name = "Group2">
      <Attribute ID="12345" Name="Sample1"/>
      <Attribute ID="12445" Name="Sample2"/>
    </Accountgroup>
  </RoleSecurity>
</Root>

I am trying to enumerate and extract all the ID corresponding to a particular Role name, workflow status and account group.

My LINQ query is working to select a node based on role name. But I am unable to proceed further. Please help!

This is my LINQ code till now.

XElement xcd = XElement.Load(strFileName);
IEnumerable<XElement> enumCust = from cust in xcd.Elements("RoleSecurity")
           where (string)cust.Attribute("Name") == strRole
           select cust;

A very useful discussion on (Elements and Decendents) [http://stackoverflow.com/questions/3705020/what-is-the-difference-between-linq-to-xml-descendants-and-elements] — TheSilverBullet, Sep 23 '13 at 06:49

score 1 · Accepted Answer · answered Sep 20 '13 at 07:29

1

Try this:

string roleName = "A";
string workflowStatus = "B";
string accountGroup = "Group1";

string xml = @"<?xml version=""1.0"" encoding=""utf-8""?>
    <Root>
        <RoleSecurity Name=""A"" Workflowstatus =""B"">
        <Accountgroup Name = ""Group1"">
            <Attribute ID=""12345"" Name=""Sample1""/>
            <Attribute ID=""12445"" Name=""Sample2""/>
        </Accountgroup>
        <Accountgroup Name = ""Group2"">
            <Attribute ID=""12345"" Name=""Sample1""/>
            <Attribute ID=""12445"" Name=""Sample2""/>
        </Accountgroup>
        </RoleSecurity>
    </Root>";

XElement element = XElement.Parse(xml);

var ids = element.Elements("RoleSecurity")
    .Where(
        e =>
            (string) e.Attribute("Name") == roleName &&
            (string) e.Attribute("Workflowstatus") == workflowStatus)
    .Elements("Accountgroup").Where(e => (string) e.Attribute("Name") == accountGroup)
    .Elements("Attribute")
    .Select(e => new {ID = (string) e.Attribute("ID"), Name = (string) e.Attribute("Name")});

answered Sep 20 '13 at 07:29

Hamlet Hakobyan

32,965
6
52
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Thanks a bunch! The miracle has happened, and code is working! :) One question about the `.Element` function. You have used it to query multiple levels. How does this work? – TheSilverBullet Sep 20 '13 at 08:34
I think you misunderstood something. At first, I use `Elements`, which returns `IEnumerable` of given node. Look at the code closer. Code traverses the levels one by other with filtering necessary content. – Hamlet Hakobyan Sep 20 '13 at 08:42
Thank you Hamlet... I realize that at each "." you go one level deep. Just wondering, how this the `Descendant` approach different? This solution has been given by one other SO user. Need to google that. – TheSilverBullet Sep 20 '13 at 09:19
`Descendants` returns all match nodes in any level from current level. – Hamlet Hakobyan Sep 20 '13 at 09:28

score 1 · Answer 2 · answered Sep 20 '13 at 07:57

Try with this approach, seems different from your (and in some aspects it really changes), but in my opinion its a good way to use fluently a LINQ query to parse an XML file, it follows XML node sequence and it's easy to understand:

  XElement element = XElement.Load(strFileName);

  var linqList = element.Elements("RoleSecurity")
                              .Where(entry => entry.Attribute("Name").Value == "A" && 
                               entry.Attribute("Workflowstatus").Value == "B")
                                  .Descendants("Accountgroup")
                                  .Where(x => x.Attribute("Name").Value == "Group1")
                                     .Descendants("Attribute")
                                     .SelectMany(id => id.Attribute("ID").Value);

Thank you for your answer! I have already implemented the accepted answer's approach. I just wonder which is a better approach for me, and why? — TheSilverBullet, Sep 20 '13 at 09:20

score 0 · Answer 3 · answered Sep 20 '13 at 07:10

0

XElement xcd = XElement.Load(strFileName);
IEnumerable<XElement> enumCust = from cust in xcd.Root.Elements("RoleSecurity")
           where cust.Attribute("Name").Value == strRole
           select cust;

This should work now you were missing .Root which is required to enumerate below the root node
and .Value to retrive the string value of the specified attribute

answered Sep 20 '13 at 07:10

Parv Sharma

12,581
4
48
80

I am trying to dril down deeper. Like I have mentioned in the question, I am trying to enumerate and extract all the ID corresponding to a particular Role name, workflow status and account group. – TheSilverBullet Sep 20 '13 at 07:12

Neel · Answer 4 · 2013-09-20T07:21:49.717

0

refer this artical :- http://www.dotnetcurry.com/ShowArticle.aspx?ID=564

foreach (XElement xcd xelement.Descendants("Id"))
    {
        Console.WriteLine((string)xcd);
    }

edited Sep 20 '13 at 07:21

answered Sep 20 '13 at 07:15

Neel

11,625
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Not able to select relevant nested nodes: LINQ

4 Answers4