How do I use PowerShell to Validate XML files against an XSD?

Question

As a part of my development I'd like to be able to validate an entire folder's worth of XML files against a single XSD file. A PowerShell function seems like a good candidate for this as I can then just pipe a list of files to it like so: dir *.xml | Validate-Xml -Schema .\MySchema.xsd

I've considered porting C# code from the Validating an Xml against Referenced XSD in C# question, but I don't know how to Add handlers in PowerShell.

Answer 1

I want to comment that the script in current accepted answer doesn't validate errors about incorrect orders of elements of xs:sequence. For example: test.xml

<addresses xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"        xsi:noNamespaceSchemaLocation='test.xsd'>   <address>     <street>Baker street 5</street>     <name>Joe Tester</name>   </address> </addresses> 

test.xsd

<xs:schema xmlns:xs='http://www.w3.org/2001/XMLSchema'>     <xs:element name="addresses">       <xs:complexType>        <xs:sequence>          <xs:element ref="address" minOccurs='1' maxOccurs='unbounded'/>        </xs:sequence>      </xs:complexType>     </xs:element>       <xs:element name="address">       <xs:complexType>        <xs:sequence>          <xs:element ref="name" minOccurs='0' maxOccurs='1'/>          <xs:element ref="street" minOccurs='0' maxOccurs='1'/>        </xs:sequence>       </xs:complexType>      </xs:element>       <xs:element name="name" type='xs:string'/>      <xs:element name="street" type='xs:string'/>     </xs:schema> 

I wrote another version that can report this error:

function Test-XmlFile {     <#     .Synopsis         Validates an xml file against an xml schema file.     .Example         PS> dir *.xml | Test-XmlFile schema.xsd     #>     [CmdletBinding()]     param (              [Parameter(Mandatory=$true)]         [string] $SchemaFile,          [Parameter(ValueFromPipeline=$true, Mandatory=$true, ValueFromPipelineByPropertyName=$true)]         [alias('Fullname')]         [string] $XmlFile,          [scriptblock] $ValidationEventHandler = { Write-Error $args[1].Exception }     )      begin {         $schemaReader = New-Object System.Xml.XmlTextReader $SchemaFile         $schema = [System.Xml.Schema.XmlSchema]::Read($schemaReader, $ValidationEventHandler)     }      process {         $ret = $true         try {             $xml = New-Object System.Xml.XmlDocument             $xml.Schemas.Add($schema) | Out-Null             $xml.Load($XmlFile)             $xml.Validate({                     throw ([PsCustomObject] @{                         SchemaFile = $SchemaFile                         XmlFile = $XmlFile                         Exception = $args[1].Exception                     })                 })         } catch {             Write-Error $_             $ret = $false         }         $ret     }      end {         $schemaReader.Close()     } } 

PS C:\temp\lab-xml-validation> dir test.xml | Test-XmlFile test.xsd

System.Xml.Schema.XmlSchemaValidationException: The element 'address' has invalid child element 'name'. ...