XML document got already a DocumentElement node when i try to load XMLReader object into XMLDocument

Question

I want to create in an app - coded with C# - a copy of the actual element of a XMLReader object by using a XMLDocument instance.

The purpose is to get a copy of the actual reader element, so i can read the inner XML from the actual XML element without moving in the original reader.

When i try to load the reader into the XMLDocument i get the error "The document already has a 'DocumentElement' node.".

Any help would be appreciated.

XmlDocument xmlDocument = new XmlDocument();
MemoryStream streamFromReader = new MemoryStream();
xmlDocument.Load(reader); //Here i get the error
xmlDocument.Save(streamFromReader);
streamFromReader.Position = 0;
XmlReader copyReader = XmlReader.Create(streamFromReader);
sb.Append(copyReader.ReadInnerXml());
copyReader.Close();

Answer 1

The answer of Markus helped me to get to the solution.

When the XMLReader is getting to an element which has subitems, i must get first the actual position within the file using the interface IXmlLineInfo.

IXmlLineInfo lineInfo = (IXmlLineInfo)reader;
int lineNumber = lineInfo.LineNumber;
int linePosition = lineInfo.LinePosition;

Then i create an instance of XmlTextReader, which reads the file to that position.

When the reminded position was arrived, the XmlTextReader contains the element and i can get the inner XML from it.

Stream stream = new MemoryStream(myFile.FileBytes);
XmlTextReader textReader = new XmlTextReader(stream);
while (textReader.LineNumber < lineNumber)
{
    textReader.Read();
}
string innerXml = textReader.ReadInnerXml());
textReader.Close();