XmlWriter.WriteString() problem.

[Tom Delany]

According to the Microsoft documentation, the .NET class
System.Xml.XmlWriter.WriteString() does the following:

"Character values in the range 0x-0x1F (excluding white space characters
0x9, 0xA, and 0xD) are replaced with numeric character entities (�
through &#0x1F)."

However, when we call WriteString() in an application we have written, we
are seeing the following exception being thrown:

System.ArgumentException: '', hexadecimal value 0x12, is an invalid
character.
at System.Xml.XmlUtf8RawTextWriter.InvalidXmlChar(Int32 ch, Byte*
pDst, Boolean entitize)
at System.Xml.XmlUtf8RawTextWriter.WriteElementTextBlock(Char* pSrc,
Char* pSrcEnd)
at System.Xml.XmlUtf8RawTextWriter.WriteString(String text)
at System.Xml.XmlUtf8RawTextWriterIndent.WriteString(String text)
at System.Xml.XmlWellFormedWriter.WriteString(String text)

Anyone ever seen anything like this? Any idea what I am doing wrong?

Tom Delany

[Martin Honnen]

Post by Tom Delany
According to the Microsoft documentation, the .NET class
"Character values in the range 0x-0x1F (excluding white space characters
0x9, 0xA, and 0xD) are replaced with numeric character entities (�
through &#0x1F)."
However, when we call WriteString() in an application we have written, we
System.ArgumentException: '', hexadecimal value 0x12, is an invalid
character.
at System.Xml.XmlUtf8RawTextWriter.InvalidXmlChar(Int32 ch, Byte*
pDst, Boolean entitize)
at System.Xml.XmlUtf8RawTextWriter.WriteElementTextBlock(Char* pSrc,
Char* pSrcEnd)
at System.Xml.XmlUtf8RawTextWriter.WriteString(String text)
at System.Xml.XmlUtf8RawTextWriterIndent.WriteString(String text)
at System.Xml.XmlWellFormedWriter.WriteString(String text)
Anyone ever seen anything like this? Any idea what I am doing wrong?

XmlTextWriter in the .NET framework 1.0/1.1 did that and XmlTextWriter
in the .NET framework 2.0 still does that but the normal XmlWriter you
create with e.g. XmlWriter.Create has been fixed to be compliant with
the XML 1.0 specification and to ensure (by default) that the output is
well-formed and even escaping those characters is not allowed in the XML
1.0 specification.
So use new XmlTextWriter to create an XmlTextWriter or if you want to
use XmlWriter.Create, then use XmlWriterSettings with CheckCharacters
set to false e.g.

XmlWriterSettings writerSettings = new XmlWriterSettings();
writerSettings.CheckCharacters = false;
using (XmlWriter xmlWriter = XmlWriter.Create("file.xml",
writerSettings))
{
// ...
}