how to create an xml using xml writer without declaration element

Question

I am using XmlWriter.Create() to get a writer instance then write the XML, but the result has the <?xml version="1.0" encoding="utf-16" ?>, how do I tell my xml writer do not produce it?

score 37 · Accepted Answer · edited Mar 01 '19 at 08:55

37

Use XmlWriterSettings.OmitXmlDeclaration.

Don't forget to set XmlWriterSettings.ConformanceLevel to ConformanceLevel.Fragment.

edited Mar 01 '19 at 08:55

Sebastian Brosch

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answered Jul 26 '11 at 16:48

Kirill Polishchuk

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From the docs you link to: `The XML declaration is always written if ConformanceLevel is set to Document, even if OmitXmlDeclaration is set to true` – Cameron Jul 26 '11 at 16:50
Won't it be set to Document most of the time? – Cameron Jul 26 '11 at 16:56
@Cameron, Strange question... `ConformanceLevel.Document` is default, but you can set `ConformanceLevel.Fragment`... – Kirill Polishchuk Jul 26 '11 at 16:58
Ah, yes, I understand know :-) You might want to add that into your answer. What about if you want the Document conformance level (e.g. to ensure a single root node), but no XML declaration? – Cameron Jul 26 '11 at 17:02
@Cameron, I think you answered your your question yourself :-) – Kirill Polishchuk Jul 26 '11 at 17:05
Kirill, forgive my ignorance, but how did @Cameron answer the question himself? – ro͢binmckenzie Jul 19 '16 at 09:10
@ro͢binmckenzie: Oh, it looks like I literally answered this question with an alternate solution (below). – Cameron Jul 19 '16 at 15:57
In .NET Core 3.1 at least, using `OmitXmlDeclaration = false` with `ConformanceLevel.Default` works fine and no XML Declaration header is written (when using `XmlDocument.Save`). – Dai Jun 18 '21 at 14:22

Cameron · Answer 2 · 2011-07-26T16:56:11.217

6

You can subclass XmlTextWriter and override the WriteStartDocument() method to do nothing:

public class XmlFragmentWriter : XmlTextWriter
{
    // Add whichever constructor(s) you need, e.g.:
    public XmlFragmentWriter(Stream stream, Encoding encoding) : base(stream, encoding)
    {
    }

    public override void WriteStartDocument()
    {
       // Do nothing (omit the declaration)
    }
}

Usage:

var stream = new MemoryStream();
var writer = new XmlFragmentWriter(stream, Encoding.UTF8);
// Use the writer ...

Reference: This blog post from Scott Hanselman.

edited Jul 26 '11 at 16:56

answered Jul 26 '11 at 16:49

Cameron

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thanks, any better way? I do not want to subclass just for the purpose of removing the declaration. – ninithepug Jul 26 '11 at 16:54
@ninithepug: Not as far as I know, sorry. You can wrap it up in a static method somewhere if you use it often, though. That should help keep it clean – Cameron Jul 26 '11 at 17:00
@ninithepug: It seems Kirill's answer (which doesn't need a new class) might be better (unless you want the Document conformance level, of course). – Cameron Jul 26 '11 at 17:08

score 2 · Answer 3 · edited Jun 20 '18 at 08:39

you can use XmlWriter.Create() with:

new XmlWriterSettings { 
    OmitXmlDeclaration = true, 
    ConformanceLevel = ConformanceLevel.Fragment 
}

    public static string FormatXml(string xml)
    {
        if (string.IsNullOrEmpty(xml))
            return string.Empty;

        try
        {
            XmlDocument document = new XmlDocument();
            document.LoadXml(xml);
            using (MemoryStream memoryStream = new MemoryStream())
            using (XmlWriter writer = XmlWriter.Create(
                memoryStream, 
                new XmlWriterSettings { 
                    Encoding = Encoding.Unicode, 
                    OmitXmlDeclaration = true, 
                    ConformanceLevel = ConformanceLevel.Fragment, 
                    Indent = true, 
                    NewLineOnAttributes = false }))
            {
                document.WriteContentTo(writer);
                writer.Flush();
                memoryStream.Flush();
                memoryStream.Position = 0;
                using (StreamReader streamReader = new StreamReader(memoryStream))
                {
                    return streamReader.ReadToEnd();
                }
            }
        }
        catch (XmlException ex)
        {
            return "Unformatted Xml version." + Environment.NewLine + ex.Message;
        }
        catch (Exception ex)
        {
            return "Unformatted Xml version." + Environment.NewLine + ex.Message;
        }
    }

how to create an xml using xml writer without declaration element

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