Multiple LINQ to XML query - linq

Question

I am trying to figure out a multiple where clause that is derived from two different elements. Basically, I want to be able to filter based on name attributes of DataType & Service elements. Appreciate any feedback. Thanks Jay
var services = from dt in doc.Descendants("DataType")
where (string)dt.Attribute("name") == "WELL_INDUSTRY" && (string)dt.Elements("Service").Attributes == "Well_Industry"
from service in dt.Elements("Services").Elements("Service").Elements("Layers").Elements("Layer")
select new
{
Name = (string)service.Attribute("name"),
};
XML:
<DataTypes>
<DataType name="WELL_INDUSTRY">
<Spatial>
<Services>
<Service name="Well_Industry" group="Well" status="Primary" >
<Layers>
<layer name="Bottom Hole Wells" ></layer>
<layer name="Bottom Hole Wells2" ></layer>
</Layers>

Answer 1

I think you're looking for something like that:
var services = from dt in doc.Descendants("DataType")
where (string)dt.Attribute("name") == "WELL_INDUSTRY"
from service in dt.Element("Spatial")
.Elements("Services")
.Elements("Service")
where (string)service.Attribute("name") == "Well_Industry"
from layer in service.Element("Layers")
.Elements("Layer")
select new
{
ServiceName = (string)service.Attribute("name"),
Layers = layer.Select(x => (string)x).ToList()
};
You can add another where after from service ....
You are still able to use service variable within select part of the query.
However, querying for ServiceName when there is ServiceName == "myName" check before seems to be useless. In case you need names of layers, use following select:
select new
{
Name = (string)layes.Attribute("name")
};

Answer 2

var services = from dt in doc.Descendants("DataType")
where (string)dt.Attribute("name") == "WELL_INDUSTRY"
from s in dt.Descendants("Service")
where (string)s.Attribute("name") == "Well_Industry"
from l in s.Descendants("Layer")
select new {
Name = (string)l.Attribute("name")
};
Same can be achieved with XPath:
var xpath = "//DataType[#name='WELL_INDUSTRY']//Service[#name='Well_Industry']//layer";
var services = from l in doc.XPathSelectElements(xpath)
select new {
Name = (string)l.Attribute("name")
};