How can I catch this XmlException thrown from third party library?

Question

I'm using the Exchange Web Services managed API and about once a day it throws an XmlException that I have no idea how to catch. Here are the exception details.

System.Xml.XmlException was unhandled
  Message="'', hexadecimal value 0x1F, is an invalid character. Line 1, position 1."
  Source="System.Xml"
  LineNumber=1
  LinePosition=1
  SourceUri=""
  StackTrace:
       at System.Xml.XmlTextReaderImpl.Throw(Exception e)
       at System.Xml.XmlTextReaderImpl.Throw(String res, String[] args)
       at System.Xml.XmlTextReaderImpl.Throw(Int32 pos, String res, String[] args)
       at System.Xml.XmlTextReaderImpl.ThrowInvalidChar(Int32 pos, Char invChar)
       at System.Xml.XmlTextReaderImpl.ParseText(Int32& startPos, Int32& endPos, Int32& outOrChars)
       at System.Xml.XmlTextReaderImpl.ParseText()
       at System.Xml.XmlTextReaderImpl.ParseDocumentContent()
       at System.Xml.XmlTextReaderImpl.Read()
       at Microsoft.Exchange.WebServices.Data.EwsXmlReader.Read()
       at Microsoft.Exchange.WebServices.Data.EwsXmlReader.Read(XmlNodeType nodeType)
       at Microsoft.Exchange.WebServices.Data.EwsXmlReader.InternalReadElement(XmlNamespace xmlNamespace, String localName, XmlNodeType nodeType)
       at Microsoft.Exchange.WebServices.Data.EwsXmlReader.ReadStartElement(XmlNamespace xmlNamespace, String localName)
       at Microsoft.Exchange.WebServices.Data.ServiceRequestBase.ReadResponse(EwsServiceXmlReader ewsXmlReader)
       at Microsoft.Exchange.WebServices.Data.HangingServiceRequestBase.ParseResponses(Object state)
       at System.Threading._ThreadPoolWaitCallback.WaitCallback_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading._ThreadPoolWaitCallback.PerformWaitCallbackInternal(_ThreadPoolWaitCallback tpWaitCallBack)
       at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback(Object state)
  InnerException:

From the stacktrace I don't see anything that would allow me to catch and fix the issue.

How can I catch this?

Do you want to catch that specific exception or on catching that exception you want to rectify that problem or you want some work-around so that the exception doesn't occur? — Siva Gopal, Jul 13 '12 at 13:46
@MikeCorcoran: I am not sending XML. The XML is being returned by Exchange. — user1480458, Jul 13 '12 at 13:54
@SivaGopal: Yes, I would like that catch that specific exception because the XML is being returned by our Exchange server, which I have no control over. — user1480458, Jul 13 '12 at 13:55
http://stackoverflow.com/questions/6693153/what-is-character-0x1f should help you fix the bug :) — Thomas Lindvall, Jul 13 '12 at 13:56

score 2 · Accepted Answer · edited May 23 '17 at 11:56

2

Your XML library doesn't support the 0x1F char, which is the unit separator char.

What you can do is escape all occurrences of this specific char before your stream/XML file/whatever/ is processed by your XML library. See How do I escape unicode character 0x1F in xml?

See allowed character ranges for XML 1.1.

edited May 23 '17 at 11:56

Community

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answered Jul 13 '12 at 13:42

ken2k

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My apologies on not being very clear. The issue is caused by the EWS library parsing the XML returned by Exchange *without* sanitizing it. Because all of this is done within the library I don't know how to catch it. – user1480458 Jul 13 '12 at 14:15

How can I catch this XmlException thrown from third party library?

1 Answers1