New-XPathExpression
Description
The New-XPathExpression
cmdlet create an XPath expression that can be used in the following manners
As an input to the Search-Resources cmdlet
As an input to the New-XPathQuery cmdlet
By using the ToString() method, you can generate an expression to use elsewhere in your script
When setting a resource attribute that expects a Filter type
The cmdlet takes a query or group generated with the New-XPathQuery or New-XPathQueryGroup cmdlets and produces an XPath expression that can be used in the manners described above.
For a full list of examples filters generated by the XPath cmdlets, see the XPath expression examples page.
Syntax
New-XpathExpression [-ObjectType] <string> [-QueryObject] <IXPathQueryObject> [[-DereferenceAttribute] <string>] [[-WrapFilterXml]]
Parameters
ObjectType
Required. The type of object to query. To search on all object types, use the value *
QueryObject
Required. The query or group generated using the New-XPathQuery or New-XPathQueryGroup cmdlet
DereferenceAttribute
Optional. Specifies a reference-type attribute to query. See the example section for more information.
WrapFilterXml
Optional. Specifies that the resulting XPath expression should be wrapped in the filter XML element used when setting the Filter
attribute on sets and groups.
Examples
Creating a basic expression
# Creates an expression that searches for users with the account name 'ryan'
$query = New-XPathQuery -AttributeName "AccountName" -Operator Equals -Value "ryan"
$expression = New-XPathExpression -ObjectType "Person" -QueryObject $query
$expression.ToString()
This returns an expression containing the query
/Person[(AccountName = 'ryan')]
Passing the expression to the Search-Resources cmdlet
The expression can be passed directly to the Search-Resources cmdlet to search for objects
# Creates an expression that searches for users with the account name 'ryan'
$query = New-XPathQuery -AttributeName "AccountName" -Operator Equals -Value "ryan"
$expression = New-XPathExpression -ObjectType "Person" -QueryObject $query
Search-Resources $expression
Building an expression to dereference an object
The expression builder supports dereferencing expressions, as supported by the Resource Management Service. The following example finds the manager of a user with the account name 'ryan'
# Creates an expression that returns the manager of a user who has the account name 'ryan'
$query = New-XPathQuery -AttributeName "AccountName" -Operator Equals -Value "ryan"
$expression = New-XPathExpression -ObjectType "Person" -QueryObject $query -DereferenceAttribute "Manager"
$expression.ToString()
This returns the following expression
/Person[(AccountName = 'ryan')]/Manager
You can also use a nested expression to find all users who have the person with the account name of 'ryan' as their manager
# Build an expression to find a user by its account name
$query = New-XpathQuery -AttributeName "AccountName" -Operator Equals -Value "ryan"
$expression = New-XpathExpression -ObjectType "Person" -Query $query
# Build a query to find all users with a manager who has the account name 'ryan'
$derefQuery = New-XpathQuery -AttributEName "Manager" -Operator Equals -Value $expression
$derefExpression = New-XpathExpression Person $derefQuery
$derefExpression.ToString()
This returns an expression containing the query
/Person[(Manager = /Person[(AccountName = 'ryan')])]
Building a filter expression
When using the expression builder to create an value to use in a Filter
attribute in a set or group, you can specify that the resulting expression should be wrapped in the XML filter element.
$query = New-XPathQuery -AttributeName "AccountName" -Operator Equals -Value "ryan"
$expression = New-XPathExpression -ObjectType "Person" -QueryObject $query -WrapFilterXml
$expression.ToString()
The resulting string is as follows
<Filter xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" Dialect="http://schemas.microsoft.com/2006/11/XPathFilterDialect" xmlns="http://schemas.xmlsoap.org/ws/2004/09/enumeration">/Person[(AccountName = 'ryan')]</Filter>
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