Odd character returned when using Encoding.UTF8.GetString(MemoryStream)

[Chris Lacey]

Is anyone aware why the following code (intended to write XML into a
memory-based XmlTextWriter, and return the complete document as a string)
produces badly formed XML due to the resultant string always commencing with
a question mark

string xmlRequestStrin g;
MemoryStream memoryStream = new MemoryStream();
XmlTextWriter xmlTextWriter = new XmlTextWriter(m emoryStream,
Encoding.UTF8);

xmlTextWriter.W riteStartDocume nt();
xmlTextWriter.W riteStartElemen t("element");
xmlTextWriter.W riteStartElemen t("subelement") ;
xmlTextWriter.W riteAttributeSt ring("attribute ", "attributeValue ");
xmlTextWriter.W riteString("str ing");
xmlTextWriter.W riteEndElement( );
xmlTextWriter.W riteEndElement( );
xmlTextWriter.W riteEndDocument ();
xmlTextWriter.C lose();

xmlRequestStrin g = Encoding.UTF8.G etString(memory Stream.ToArray( ));
Console.WriteLi ne(xmlRequestSt ring);


This returns the following (note the preceding question mark):

?<?xml version="1.0" encoding="utf-8"?><element><s ubelement
attribute="attr ibute
Value">string</subelement></element>

Any ideas or assistance very gratefully received!!

Many thanks,

Chris.

[Jon Skeet [C# MVP]]

Re: Odd character returned when using Encoding.UTF8.G etString(Memory Stream)

Chris Lacey <chris.lacey@bi gfoot.com> wrote:[color=blue]
> Is anyone aware why the following code (intended to write XML into a
> memory-based XmlTextWriter, and return the complete document as a string)
> produces badly formed XML due to the resultant string always commencing with
> a question mark[/color]

<snip>

It's a byte ordering mark. If instead of using Encoding.UTF8.G etString
you use a StreamReader, you'll see it goes away.

If you really only want the characters, I suggest that you change to
using a StringWriter instead of a MemoryStream. To support appropriate
encodings, you may wish to derive a class from StringWriter to allow
you to specify the encoding, e.g.

public class StringWriterWit hEncoding : StringWriter
{
Encoding encoding;

public StringWriterWit hEncoding (Encoding encoding)
{
this.encoding = encoding;
}

public override Encoding Encoding
{
get { return encoding; }
}
}

--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too

[Oleg Tkachenko]

Re: Odd character returned when using Encoding.UTF8.G etString(Memory Stream)

Chris Lacey wrote:
[color=blue]
> Is anyone aware why the following code (intended to write XML into a
> memory-based XmlTextWriter, and return the complete document as a string)
> produces badly formed XML due to the resultant string always commencing with
> a question mark[/color]

Most likely it's not question mark, but BOM - byte order mark.
Btw, why don't you write directly to string using StringWriter?
--
Oleg Tkachenko
XML Insider

http://www.tkachenko.com/blog