使用Powershell v2.0和XPATH读取包含多个属性的xml组件

Question

I cannot find a suitable answer to this as all the examples relate to a regular or standard form of XML structure. I am trying to search a directory of xml files, and I want to limit to those that have a particular "OrderDate" attribute specified in the xml. So the PS script is to filter to a particular value, but I am unable to get PS to reference this attribute.

<?xml version="1.0"?>
<Order Value="28.78" Lines="3" OrderDate="2016-03-21" SupplierName="ASupplier" OrderNo="1234">
<Line UnitCost="5.28" PackSize="Box 44" Quantity="1" ImpExpRef="1234" LineNo="1"/>
<Line UnitCost="18" PackSize="Box180" Quantity="1" ImpExpRef="1234" LineNo="2"/>
<Line UnitCost="5.5" PackSize="5Ltr" Quantity="1" ImpExpRef="1234" LineNo="3"/>
</Order>

As you can see, there are two nodes (or elements?): Order and Line, and there multiple attributes for each and don't have their own node, so I can't work out how to XPATH this file.

The current script just to isolate the attribute is:

[xml]$XmlDocument = Get-content "C:\example.xml"
$XPath = '//Order[@OrderDate]'    
$nodes = Select-Xml $XmlDocument -XPATH $xpath | Select-Object -ExpandProperty Node

and the results are:

PS C:\Windows\system32> $nodes

OrderNo      : 1234
SupplierName : ASupplier
OrderDate    : 2016-03-21
Lines        : 3
Value        : 28.78
Line         : {Line, Line, Line}

It doesn't recognise @OrderDate as an attribute, or any other attribute for that matter, presumably because there are multiple attributes under "Order", it's as if it's ignoring it. Same result if $XPath = '//Order[@*]'

All examples I have researched assume one attribute per node (or element)

Answer 1

"I tried what you suggested but it doesn't return any values as if it ignores it"

I maybe missing something about how you tried it or what you are trying to achieve actually (please clarify). The following is what I did exactly , and it returned the expected element :

PS C:\Users\Foo> $XmlDocument = [xml]@"
>> <Order Value="28.78" Lines="3" OrderDate="2016-03-21" SupplierName="ASupplier" OrderNo="1234">
>> <Line UnitCost="5.28" PackSize="Box 44" Quantity="1" ImpExpRef="1234" LineNo="1"/>
>> <Line UnitCost="18" PackSize="Box180" Quantity="1" ImpExpRef="1234" LineNo="2"/>
>> <Line UnitCost="5.5" PackSize="5Ltr" Quantity="1" ImpExpRef="1234" LineNo="3"/>
>> </Order>
>> "@
>>
PS C:\Users\Foo> $XPath = "//Order[@OrderDate='2016-03-21']"
PS C:\Users\Foo> $nodes = Select-Xml $XmlDocument -XPATH $xpath | Select-Object -ExpandProperty Node
PS C:\Users\Foo> $nodes


Value        : 28.78
Lines        : 3
OrderDate    : 2016-03-21
SupplierName : ASupplier
OrderNo      : 1234
Line         : {Line, Line, Line}

UPDATE :

In response to your comment below, the XPath //Order[@OrderDate='2016-03-21'] returns Order element that have certain OrderDate attribute value. By Order element I mean the entire element leaving none of its part. You can't return Order element that contains only one attribute ie OrderDate attribute, because there is no such element in the original XML. You can, however, returns just the target attribute using the following XPath :

//Order/@OrderDate[.='2016-03-21']