XML fails validation get Xpath to faulting element [Answered] RSS

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  gilesrpa

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  6 Points

  23 Posts

  XML fails validation get Xpath to faulting element

  Dec 11, 2013 06:53 AM|gilesrpa|LINK

  I am using the following code to validate my xml source.

  Public Shared Sub ValidateSuppliedXMLData(ByVal _xDoc As MemoryStream, ByVal _SchemaFileName As String)
          Try
              Dim _xmlSetting As XmlReaderSettings = New XmlReaderSettings()
              _xmlSetting.Schemas.Add("urn:dis:supplierengagement:v02", _SchemaFileName)
              _xmlSetting.ValidationType = ValidationType.Schema
  
              Dim _xmlReader As XmlReader = XmlReader.Create(_xDoc, _xmlSetting)
              Dim _doc As XmlDocument = New XmlDocument()
  
              Dim _xmlHandler As ValidationEventHandler = New ValidationEventHandler(AddressOf ValidationEventHandler)
  
              _doc.Load(_xmlReader)
  
              _doc.Validate(_xmlHandler)
  
              _xmlReader.Close()
          Catch xm As XmlSchemaValidationException
              Throw New Exception(xm.Message)
          Catch ex As Exception
              Throw New Exception(ex.Message)
          End Try
      End Sub
      Private Shared Sub ValidationEventHandler(ByVal sender As Object, ByVal args As ValidationEventArgs)
  
          Select Case args.Severity
              Case XmlSeverityType.Error
                  ' Oh dear
                  Throw New Exception(args.Exception.Message)
              Case XmlSeverityType.Warning
                  ' Not so bad
                  Throw New Exception(args.Exception.Message)
          End Select
  
  
      End Sub

  When I introduce an validation error in the code, I wish to recover the xpath to the faulting element.

  The code above stops when the line

  _doc.Load(_xmlReader)
  

  is executed, and fails with a validation error within the

  Catch xm As XmlSchemaValidationException
        Throw New Exception(xm.Message)
  

  code block.

  What am I doing wrong and will this product the xpath to the error?

  XPATH xml Schema validation

• • Reply
  Terry Guo -...

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  12777 Points

  1635 Posts

  Re: XML fails validation get Xpath to faulting element

  Dec 12, 2013 02:52 AM|Terry Guo - MSFT|LINK

  Hi gilesrpa,

  If you want to validate your xml source, I suggest you using XmlValidatingReader to achieve it.

  There have a sample:

  Public Shared Sub Main()
           Dim tr As New XmlTextReader("HeadCount.xml")
           Dim vr As New XmlValidatingReader(tr)
           
           vr.ValidationType = ValidationType.Schema
           AddHandler vr.ValidationEventHandler, AddressOf ValidationHandler
           
           While vr.Read()
              PrintTypeInfo(vr)
              If vr.NodeType = XmlNodeType.Element Then
                 While vr.MoveToNextAttribute()
                    PrintTypeInfo(vr)
                 End While
              End If
           End While
           Console.WriteLine("Validation finished")
        End Sub
        ' Main
        
        
        Public Shared Sub PrintTypeInfo(vr As XmlValidatingReader)
           If Not (vr.SchemaType Is Nothing) Then
              If TypeOf vr.SchemaType Is XmlSchemaDatatype Or TypeOf vr.SchemaType Is XmlSchemaSimpleType Then
                 Dim value As Object = vr.ReadTypedValue()
                 Console.WriteLine("{0}({1},{2}):{3}", vr.NodeType, vr.Name, value.GetType().Name, value)
              Else
                 If TypeOf vr.SchemaType Is XmlSchemaComplexType Then
                    Dim sct As XmlSchemaComplexType = CType(vr.SchemaType, XmlSchemaComplexType)
                    Console.WriteLine("{0}({1},{2})", vr.NodeType, vr.Name, sct.Name)
                 End If
              End If
           End If
        End Sub
        ' PrintTypeInfo
         
        Public Shared Sub ValidationHandler(sender As Object, args As ValidationEventArgs)
           Console.WriteLine("***Validation error")
           Console.WriteLine("Severity:{0}", args.Severity)
           Console.WriteLine("Message:{0}", args.Message)
        End Sub

  More information please refer to:
  http://msdn.microsoft.com/en-us/library/thydszwy(v=vs.110).aspx?cs-save-lang=1&cs-lang=vb#code-snippet-2

  Hope it helps.

  Best Regards,
  Terry Guo

  XPATH xml Schema validation