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XML String with no parent node to JSON with C#

I have an XML string that does not contain a parent node. This XML is a representation of a json request for an API. It seems pointless, but it is done this way to make it easy for non programmers to read the file. In order to convert the XML to json, pretty much everything i have seen says to convert the string to an XMLDocument and then use the following to get the json.
string jsonText = JsonConvert.SerializeXmlNode(doc);
The problem i have here is that the xml is not really valid and because of this, it cannot be converted to an xml document. What i really want is to be able to do this.
string jsonText = JsonConvert.SerializeXmlNode(doc.InnerXml);
This doesnt work since innerXML is a string and not an object. I have been able to get it to work by creating a root element and then just using a sub string to cut the resulting string, but this seems pointless. There has to be a better way to do this without having to add xml only to have to remove it from the json afterwards. Is it possible to convert a piece of xml like the xml below into json like the example below.
<rootnode>
<fielda>a</fielda>
<fieldb>b</fieldb>
</rootnode>
Converts to
{
"fielda": "a",
"fieldb": "b"
}

There's an overload of SerializeXmlNode that takes a boolean omitRootObject:
string jsonText = JsonConvert.SerializeXmlNode(doc, Formatting.None, true);

JsonConvert.SerializeXmlNode has an overloaded method which you could use to ignore root.
string jsonText = JsonConvert.SerializeXmlNode(doc, Formatting.None, true);
Third parameter is for omitting RootObject

"An error occurred while parsing EntityName" after grabbing content from valid XML

I am reading an XML string with XDocument
XmlReader reader = XmlReader.Create(new StringReader(xmltext));
reader.Read();
XDocument xdoc = XDocument.Load(reader);
Then I grab the content of some tags and put them within tags in a different string.
When I try to Load this string in the same way I did with the first, I get an error "An error occurred while parsing EntityName. Line 1, position 344.".
I think it should be parsed correctly since it has beem parsed before so I guess I am missing something here.
I am reading and copying the content of the first XML with (string)i.Element("field").
I am using .net 4

When I grab the content of the xml that I want to use for building another Xml string I use (string)i.Element("field") and this is converting my Xml into string. My next Xml Parsing does not recognize it as an Element anymore so I solved the problem by not using (string) before I read my element, just i.Element("field") and this works.

It sounds like you've got something like this:
<OriginalDocument>
<Foo>A & B</Foo>
</OriginalDocument>
That A & B represents the text A & B. So when you grab the text from the element, you'll get the string "A & B". If you then use that to build a new element like this:
string foo = "<Foo>" + fooText + "</Foo>";
then you'll end up with invalid XML like this:
<Foo>A & B</Foo>
Basically, you shouldn't be constructing XML in text form. It's not clear what you're really trying to achieve, but you can copy an element from one place to another pretty easily in XElement form; you shouldn't need to build a string and then reparse it.

So after spending hours on this issue:
it turns out that if you have an ampersand symbol ("&") or any other XML escape characters within your xml string, it will always fail will you try read the XML.
TO solve this, replace the special characters with their escaped string format
YourXmlString = YourXmlString.Replace("'", "&apos;").Replace("\"", """).Replace(">", ">").Replace("<", "<").Replace("&", "&");

How to stop XDocument.Save writing escape chars

I'm reading XML data from a varchar column in a SQL db, into a linq to sql XElement belonging to an XDocument.
When I execute the XDocument.Save method, the XML is written to file but includes the escape characters. For example, ">" is changed to "&gt".
Is there an easy way to prevent this?

First, there seems to be no reason to prevent it. Like kenny mentioned, unless special characters are XML encoded, no parser would be able to parse produced XML (because '<' or '>' characters means a lot for that parser). Second, when your parser decodes XML (e.g. you call XElement.Value), all special characters will be converted back to what they originally were. Finally, if you want to keep the original string (e.g. for purposes other than XML parsing), you can use CDATA, which in case of Linq2XML is represented by XCData class.
EDIT: As Rob pointed out, I might have gotten it wrong. If the point is to save add existing XML to a document, without special characters appear, use the following code:
XDocument document = new XDocument();
var xmlFromDb = "<xml>content</xml>";
using (var stream = new MemoryStream(Encoding.UTF8.GetBytes(xmlFromDb)))
{
using (var reader = XmlReader.Create(stream)) {
reader.MoveToContent();
document.Add(XElement.ReadFrom(reader));
}
}

C# Special Characters not displayed propely in XML

i have a string that contains special character like (trademark sign etc). This string is set as an XML node value. But the special character is not rendered properly in XML, shows ??. This is how im using it.
String str=xxxx; //special character string
XmlNode node = new XmlNode();
node.InnerText = xxxx;
I tried HttpUtility.htmlEncode(xxxx) but it converts it into "&amp ;#8482;" so the output of xml is "&#8482"; instead of ™
I have also tried XmlConvert.ToString() and XmlConvert.EncodeName but it gives ??

I strongly suspect that the problem is how you're viewing the XML. Have you made sure that whatever you're viewing it in is using the right encoding?
If you save the XML and then reload it and fetch the inner text as a string, does it have the right value? If so, where's the problem?
You shouldn't perform extra encoding yourself - let the XML APIs do their job.

I've had issues with some characters using htmlEncode() before, as well. Here's a good example of different ways to write your XML: Different Ways to Escape an XML String in C#. Check out #3 (System.Security.SecurityElement.Escape()) and #4 (System.Xml.XmlTextWriter), these are the methods I typically use.

XML Exception: Invalid Character(s)

I am working on a small project that is receiving XML data in string form from a long running application. I am trying to load this string data into an XDocument (System.Xml.Linq.XDocument), and then from there do some XML Magic and create an xlsx file for a report on the data.
On occasion, I receive the data that has invalid XML characters, and when trying to parse the string into an XDocument, I get this error.
[System.Xml.XmlException]
Message: '?', hexadecimal value 0x1C, is an invalid character.
Since I have no control over the remote application, you could expect ANY kind of character.
I am well aware that XML has a way where you can put characters in it such as &#x1C or something like that.
If at all possible I would SERIOUSLY like to keep ALL the data. If not, than let it be.
I have thought about editing the response string programatically, then going back and trying to re-parse should an exception be thrown, but I have tried a few methods and none of them seem successful.
Thank you for your thought.
Code is something along the line of this:
TextReader tr;
XDocument doc;
string response; //XML string received from server.
...
tr = new StringReader (response);
try
{
doc = XDocument.Load(tr);
}
catch (XmlException e)
{
//handle here?
}

You can use the XmlReader and set the XmlReaderSettings.CheckCharacters property to false. This will let you to read the XML file despite the invalid characters. From there you can import pass it to a XmlDocument or XDocument object.
You can read a little more about in my blog.
To load the data to a System.Xml.Linq.XDocument it will look a little something like this:
XDocument xDocument = null;
XmlReaderSettings xmlReaderSettings = new XmlReaderSettings { CheckCharacters = false };
using (XmlReader xmlReader = XmlReader.Create(filename, xmlReaderSettings))
{
xmlReader.MoveToContent();
xDocument = XDocument.Load(xmlReader);
}
More information can be found here.

XML can handle just about any character, but there are ranges, control codes and such, that it won't.
Your best bet, if you can't get them to fix their output, is to sanitize the raw data you're receiving. You need replace illegal characters with the character reference format you noted.
(You can't even resort to CDATA, as there is no way to escape these characters there.)

Would something as described in this blog post be helpful?
Basically, he creates a sanitizing xml stream.

If your input is not XML, you should use something like Tidy or Tagsoup to clean the mess up.
They would take any input and try, hopefully, to make a useful DOM from it.
I don't know how relevant dark side libraries are called.

Garbage In, Garbage Out. If the remote application is sending you garbage, then that's all you'll get. If they think they're sending XML, then they need to be fixed. In this case, you're not doing them any favors by working around their bug.
You should also make sure of what they think they're sending. What did the %1C mean to them? What did they want it to be?

IMHO the best solution would be to modify the code/program/whatever produced the invalid XML that is being fed to your program. Unfortunately this is not always possible. In this case you need to escape all characters < 0x20 before trying to load the document.

If you really can't fix the source XML data, consider taking an approach like I described in this answer. Basically, you create a TextReader subclass (e.g StripTextReader) that wraps an existing TextReader (tr) and discards invalid characters.

Its a late answer, but may help someone. When you read or serialize an XML it may have 1 invisible character at the beginning of the XML. XDocument don't like this invisible character.
So while reading the XML, just start reading from the first < character:
var myXml = XDocument.Parse(loadedString.Substring(loadedString.IndexOf("<")));
That's it and it loads just fine.