What is the simplest way to get indented XML with

Question

When I build XML up from scratch with XmlDocument, the OuterXml property already has everything nicely indented with line breaks. However, if I call LoadXml on some very "compressed" XML (no line breaks or indention) then the output of OuterXml stays that way. So ...

What is the simplest way to get beautified XML output from an instance of XmlDocument?

Answer 1

Or even easier if you have access to Linq

try
{
    RequestPane.Text = System.Xml.Linq.XElement.Parse(RequestPane.Text).ToString();
}
catch (System.Xml.XmlException xex)
{
            displayException("Problem with formating text in Request Pane: ", xex);
}

Answer 2

XmlTextWriter xw = new XmlTextWriter(writer);
xw.Formatting = Formatting.Indented;

Answer 3

As adapted from Erika Ehrli's blog, this should do it:

XmlDocument doc = new XmlDocument();
doc.LoadXml("<item><name>wrench</name></item>");
// Save the document to a file and auto-indent the output.
using (XmlTextWriter writer = new XmlTextWriter("data.xml", null)) {
    writer.Formatting = Formatting.Indented;
    doc.Save(writer);
}

Answer 4

A simple way is to use:

writer.WriteRaw(space_char);

Like this sample code, this code is what I used to create a tree view like structure using XMLWriter :

private void generateXML(string filename)
        {
            using (XmlWriter writer = XmlWriter.Create(filename))
            {
                writer.WriteStartDocument();
                //new line
                writer.WriteRaw("\n");
                writer.WriteStartElement("treeitems");
                //new line
                writer.WriteRaw("\n");
                foreach (RootItem root in roots)
                {
                    //indent
                    writer.WriteRaw("\t");
                    writer.WriteStartElement("treeitem");
                    writer.WriteAttributeString("name", root.name);
                    writer.WriteAttributeString("uri", root.uri);
                    writer.WriteAttributeString("fontsize", root.fontsize);
                    writer.WriteAttributeString("icon", root.icon);
                    if (root.children.Count != 0)
                    {
                        foreach (ChildItem child in children)
                        {
                            //indent
                            writer.WriteRaw("\t");
                            writer.WriteStartElement("treeitem");
                            writer.WriteAttributeString("name", child.name);
                            writer.WriteAttributeString("uri", child.uri);
                            writer.WriteAttributeString("fontsize", child.fontsize);
                            writer.WriteAttributeString("icon", child.icon);
                            writer.WriteEndElement();
                            //new line
                            writer.WriteRaw("\n");
                        }
                    }
                    writer.WriteEndElement();
                    //new line
                    writer.WriteRaw("\n");
                }

                writer.WriteEndElement();
                writer.WriteEndDocument();

            }

        }

This way you can add tab or line breaks in the way you are normally used to, i.e. \t or \n

Answer 5

When implementing the suggestions posted here, I had trouble with the text encoding. It seems the encoding of the XmlWriterSettings is ignored, and always overridden by the encoding of the stream. When using a StringBuilder, this is always the text encoding used internally in C#, namely UTF-16.

So here's a version which supports other encodings as well.

IMPORTANT NOTE: The formatting is completely ignored if your XMLDocument object has its preserveWhitespace property enabled when loading the document. This had me stumped for a while, so make sure not to enable that.

My final code:

public static void SaveFormattedXml(XmlDocument doc, String outputPath, Encoding encoding)
{
    XmlWriterSettings settings = new XmlWriterSettings();
    settings.Indent = true;
    settings.IndentChars = "\t";
    settings.NewLineChars = "\r\n";
    settings.NewLineHandling = NewLineHandling.Replace;

    using (MemoryStream memstream = new MemoryStream())
    using (StreamWriter sr = new StreamWriter(memstream, encoding))
    using (XmlWriter writer = XmlWriter.Create(sr, settings))
    using (FileStream fileWriter = new FileStream(outputPath, FileMode.Create))
    {
        if (doc.ChildNodes.Count > 0 && doc.ChildNodes[0] is XmlProcessingInstruction)
            doc.RemoveChild(doc.ChildNodes[0]);
        // save xml to XmlWriter made on encoding-specified text writer
        doc.Save(writer);
        // Flush the streams (not sure if this is really needed for pure mem operations)
        writer.Flush();
        // Write the underlying stream of the XmlWriter to file.
        fileWriter.Write(memstream.GetBuffer(), 0, (Int32)memstream.Length);
    }
}

This will save the formatted xml to disk, with the given text encoding.

Answer 6

If the above Beautify method is being called for an XmlDocument that already contains an XmlProcessingInstruction child node the following exception is thrown:

Cannot write XML declaration. WriteStartDocument method has already written it.

This is my modified version of the original one to get rid of the exception:

private static string beautify(
    XmlDocument doc)
{
    var sb = new StringBuilder();
    var settings =
        new XmlWriterSettings
            {
                Indent = true,
                IndentChars = @"    ",
                NewLineChars = Environment.NewLine,
                NewLineHandling = NewLineHandling.Replace,
            };

    using (var writer = XmlWriter.Create(sb, settings))
    {
        if (doc.ChildNodes[0] is XmlProcessingInstruction)
        {
            doc.RemoveChild(doc.ChildNodes[0]);
        }

        doc.Save(writer);
        return sb.ToString();
    }
}

It works for me now, probably you would need to scan all child nodes for the XmlProcessingInstruction node, not just the first one?

---

Update April 2015:

Since I had another case where the encoding was wrong, I searched for how to enforce UTF-8 without BOM. I found this blog post and created a function based on it:

private static string beautify(string xml)
{
    var doc = new XmlDocument();
    doc.LoadXml(xml);

    var settings = new XmlWriterSettings
    {
        Indent = true,
        IndentChars = "\t",
        NewLineChars = Environment.NewLine,
        NewLineHandling = NewLineHandling.Replace,
        Encoding = new UTF8Encoding(false)
    };

    using (var ms = new MemoryStream())
    using (var writer = XmlWriter.Create(ms, settings))
    {
        doc.Save(writer);
        var xmlString = Encoding.UTF8.GetString(ms.ToArray());
        return xmlString;
    }
}