Linq to Select a Parent based on Attribute of a Nested Child

Question

I am using System.Xml.Linq in order to get the information I need from this XML file. I need to end up with a List of the referenceId's that have the correct entityType in the child element.

Here is a sample of the XML file I am working with.

<PropertySetBindings>
<PropertySetBind referenceId="assemblies">
  <Rules>
    <Include entityType="IfcElementAssembly" subtypes="true" />
  </Rules>
</PropertySetBind>
<PropertySetBind referenceId="beam_common">
  <Rules>
    <Include entityType="IfcBeam" subtypes="false" />
  </Rules>  
</PropertySetBind>
<PropertySetBind referenceId="column_common">
  <Rules>
    <Include entityType="IfcColumn" subtypes="false" />
  </Rules>  
</PropertySetBind>

This is the best Linq query I can come up with, but it doesn't return anything. Nothing seems to work as soon as I try to query the attributes

 var bindings = xElement.Elements("PropertySetBindings")
   .Elements("PropertySetBind")
   .Where(x => x.Elements("Rules")
   .Elements("Include")                           
   .Attributes("entityType").FirstOrDefault().Equals("IfcBeam"))
   .Select(x => x.Attribute("referenceId"));

I think this might have to do with accessing the value of the attribute. There is no property for Attributes("entityType").Value Also, if I try to simply return all the "entityType" attributes, it returns the name and value of the attribute:

I think this query is complex for a couple reasons.

Depth of the XML Tree (nested children).
The need to use the attribute values.

Let me know if anyone knows how to do this type of Linq query.

.Attributes("entityType").FirstOrDefault().Value == "IfcBeam") — Charlieface
– Charlieface, Commented Jul 1, 2022 at 13:14

SynerCoder · Accepted Answer · 2022-07-01 13:07:54Z

1

var referenceIds = xElement.Element("PropertySetBindings")
    .Elements("PropertySetBind")
    .Where(x => x.Elements("Rules")
        .Any(r => r.Elements("Include")
            .Any(i => i.Attributes("entityType")
                .Any(a => a.Value == "IfcBeam")
            )
        )
    )
    .Select(x => x.Attribute("referenceId"))
    .Where(x => x != null)
    .Select(x => x.Value);

It works as follows:

select the PropertySetBindings element
select the PropertySetBind children
filter the children to children with Rules elements, that have Include elements that have entityType attributes, that have a value of 'IfcBeam'.
from those PropertySetBind elements, select the 'referenceId' attribute
check for null (attribute exists)
select the value of the attribute (so you dont have the "referenceId=value", just the value)

answered Jul 1, 2022 at 13:07

SynerCoder

12.9k5 gold badges51 silver badges84 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Ryan Daley Over a year ago

Thank you! I'm learning a lot from your fancy pants query!

SynerCoder Over a year ago

If this helps you, consider an upvote, or marking this answer as accepted. This is an easy way for the community to see that it is a good answer.

Ryan Daley · Accepted Answer · 2022-07-01 13:08:25Z

0

Okay, I found a working solution! I can only get it to work with using this query notation (I think its called) instead of the Lambda notation. This allows for accessing the value of the attribute.

            var bindings = from binding in xElement.Elements("PropertySetBindings")
                       from bind in binding.Elements("PropertySetBind")
                       from ru in bind.Elements("Rules")
                       from inc in ru.Elements("Include")
                       where (string)inc.Attribute("entityType") == "IfcBeam"
                       select bind.Attribute("referenceId").Value;

Let me know if you have a more elegant solution to this problem.

answered Jul 1, 2022 at 13:08

Ryan Daley

156 bronze badges

Comments

Michalor · Accepted Answer · 2022-07-01 13:33:55Z

0

Found this solution:

 var bindings = xElement.Elements("PropertySetBindings")
    .Elements("PropertySetBind")                       
    .Where(x => x.Elements("Rules").FirstOrDefault()
    .Elements("Include").FirstOrDefault()                         
    .Attributes("entityType").FirstOrDefault().Value.Equals("IfcBeam"))
    .Select(x => x.Attributes("referenceId").FirstOrDefault().Value);

answered Jul 1, 2022 at 13:33

Michalor

3774 silver badges15 bronze badges

Collectives™ on Stack Overflow

Linq to Select a Parent based on Attribute of a Nested Child

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related