I am using a third-party DLL which transmits an XML document over the internet.
Why would the DLL be throwing the following exception?
Data at the root level is invalid. Line 1, position 1. (see below for full exception text.)
Here are the first few lines of the XML Document:
<?xml version="1.0" encoding="utf-8"?> <REQUEST> <HEADER>
<REQUESTID>8a5f6d56-d56d-4b7b-b7bf-afcf89cd970d</REQUESTID>
<MESSAGETYPE>101</MESSAGETYPE>
<MESSAGEVERSION>3.0.2</MESSAGEVERSION>
Exception:
System.ApplicationException was caught
Message=Unexpected exception.
Source=FooSDK
StackTrace:
at FooSDK.RequestProcessor.Send(String SocketServerAddress, Int32 port)
at Foo.ExecuteRequest(Int32 messageID, IPayload payload, Provider prov)
at Foo.SendOrder(Int32 OrderNo)
InnerException: System.Xml.XmlException
LineNumber=1
LinePosition=1
Message=Data at the root level is invalid. Line 1, position 1.
Source=System.Xml
SourceUri=""
StackTrace:
at System.Xml.XmlTextReaderImpl.Throw(Exception e)
at System.Xml.XmlTextReaderImpl.Throw(String res, String arg)
at System.Xml.XmlTextReaderImpl.ParseRootLevelWhitespace()
at System.Xml.XmlTextReaderImpl.ParseDocumentContent()
at System.Xml.XmlTextReaderImpl.Read()
at System.Xml.XmlLoader.Load(XmlDocument doc, XmlReader reader, Boolean preserveWhitespace)
at System.Xml.XmlDocument.Load(XmlReader reader)
at System.Xml.XmlDocument.LoadXml(String xml)
at XYZ.RequestProcessor.GetObjectFromXML(String xmlResult)
at XYZ.RequestProcessor.Send(String SocketServerAddress, Int32 port)
InnerException:
I eventually figured out there was a byte mark exception and removed it using this code:
if you are using
XDocument.Load(url);
to fetch xml from another domain, it's possible that the host will reject the request and return and unexpected (non-xml) result, which results in the above XmlExceptionSee my solution to this eventuality here: XDocument.Load(feedUrl) returns "Data at the root level is invalid. Line 1, position 1."
I can give you two advices:
Remove everything before
<?xml version="1.0" encoding="utf-8"?>
Sometimes, there is some "invisible" (not visible in all text editors). Some programs add this.
It's called BOM, you can read more about it here: https://en.wikipedia.org/wiki/Byte_order_mark#Representations_of_byte_order_marks_by_encoding