Format XML string to print friendly XML string

Use XmlTextWriter...

public static string PrintXML(string xml)
{
    string result = "";

    MemoryStream mStream = new MemoryStream();
    XmlTextWriter writer = new XmlTextWriter(mStream, Encoding.Unicode);
    XmlDocument document = new XmlDocument();

    try
    {
        // Load the XmlDocument with the XML.
        document.LoadXml(xml);

        writer.Formatting = Formatting.Indented;

        // Write the XML into a formatting XmlTextWriter
        document.WriteContentTo(writer);
        writer.Flush();
        mStream.Flush();

        // Have to rewind the MemoryStream in order to read
        // its contents.
        mStream.Position = 0;

        // Read MemoryStream contents into a StreamReader.
        StreamReader sReader = new StreamReader(mStream);

        // Extract the text from the StreamReader.
        string formattedXml = sReader.ReadToEnd();

        result = formattedXml;
    }
    catch (XmlException)
    {
        // Handle the exception
    }

    mStream.Close();
    writer.Close();

    return result;
}

This one, from kristopherjohnson is heaps better:

1. It doesn't require an XML document header either.
2. Has clearer exceptions
3. Adds extra behaviour options: OmitXmlDeclaration = true, NewLineOnAttributes = true
4. Less lines of code

In newer C#:

    static string PrettyXml(string xml)
    {
        StringBuilder stringBuilder = new();
        XElement element = XElement.Parse(xml);
        XmlWriterSettings settings = new()
        {
            OmitXmlDeclaration = true,
            Indent = true,
            NewLineOnAttributes = true
        };
        using XmlWriter xmlWriter = XmlWriter.Create(stringBuilder, settings);
        element.Save(xmlWriter);
        return stringBuilder.ToString();
    }

Or, in older C#:

    static string PrettyXml(string xml)
    {
        var stringBuilder = new StringBuilder();
 
        var element = XElement.Parse(xml);
 
        var settings = new XmlWriterSettings();
        settings.OmitXmlDeclaration = true;
        settings.Indent = true;
        settings.NewLineOnAttributes = true;
 
        using (var xmlWriter = XmlWriter.Create(stringBuilder, settings))
        {
            element.Save(xmlWriter);
        }
 
        return stringBuilder.ToString();
    }

The simple solution that is working for me:

        XmlDocument xmlDoc = new XmlDocument();
        StringWriter sw = new StringWriter();
        xmlDoc.LoadXml(rawStringXML);
        xmlDoc.Save(sw);
        String formattedXml = sw.ToString();

Check the following link: How to pretty-print XML (Unfortunately, the link now returns 404 :()

The method in the link takes an XML string as an argument and returns a well-formed (indented) XML string.

I just copied the sample code from the link to make this answer more comprehensive and convenient.

public static String PrettyPrint(String XML)
{
    String Result = "";

    MemoryStream MS = new MemoryStream();
    XmlTextWriter W = new XmlTextWriter(MS, Encoding.Unicode);
    XmlDocument D   = new XmlDocument();

    try
    {
        // Load the XmlDocument with the XML.
        D.LoadXml(XML);

        W.Formatting = Formatting.Indented;

        // Write the XML into a formatting XmlTextWriter
        D.WriteContentTo(W);
        W.Flush();
        MS.Flush();

        // Have to rewind the MemoryStream in order to read
        // its contents.
        MS.Position = 0;

        // Read MemoryStream contents into a StreamReader.
        StreamReader SR = new StreamReader(MS);

        // Extract the text from the StreamReader.
        String FormattedXML = SR.ReadToEnd();

        Result = FormattedXML;
    }
    catch (XmlException)
    {
    }

    MS.Close();
    W.Close();

    return Result;
}

I tried:

internal static void IndentedNewWSDLString(string filePath)
{
    var xml = File.ReadAllText(filePath);
    XDocument doc = XDocument.Parse(xml);
    File.WriteAllText(filePath, doc.ToString());
}

it is working fine as expected.

It is possible to pretty-print an XML string via a streaming transformation with XmlWriter.WriteNode(XmlReader, true). This method

copies everything from the reader to the writer and moves the reader to the start of the next sibling.

Define the following extension methods:

public static class XmlExtensions
{
    public static string FormatXml(this string xml, 
                                   bool indent = true, bool newLineOnAttributes = false, string indentChars = "  ", 
                                   ConformanceLevel conformanceLevel = ConformanceLevel.Document, bool ignoreWhitespace = true) => 
        // By default we ignore the incoming whitespace, since the purpose of this method is to reformat the incoming xml.
        xml.FormatXml( new XmlWriterSettings { Indent = indent, NewLineOnAttributes = newLineOnAttributes, IndentChars = indentChars, ConformanceLevel = conformanceLevel }, 
                      new XmlReaderSettings { ConformanceLevel = conformanceLevel, IgnoreWhitespace = ignoreWhitespace });

    public static string FormatXml(this string xml, XmlWriterSettings writerSettings, XmlReaderSettings? readerSettings = default)
    {
        using (var textReader = new StringReader(xml))
        using (var xmlReader = XmlReader.Create(textReader, readerSettings ))
        using (var textWriter = new StringWriter())
        {
            using (var xmlWriter = XmlWriter.Create(textWriter, writerSettings))
                xmlWriter.WriteNode(xmlReader, true);
            return textWriter.ToString();
        }
    }
}

And now you will be able to do:

var inXml = @"<?xml version='1.0'?><response><error code='1'> Success</error></response>";
var newXml = inXml.FormatXml(indentChars : "", newLineOnAttributes : false); // Or true, if you prefer
Console.WriteLine(newXml);

Which prints

<?xml version='1.0'?>
<response>
<error code="1"> Success</error>
</response>

Notes:

• Other answers load the XML into some Document Object Model such as XmlDocument or XDocument/XElement, then re-serialize the DOM with indentation enabled.

  This streaming solution completely avoids the added memory overhead of a DOM.

• In your question you do not add any indentation for the nested <error code='1'> Success</error> node, so I set indentChars : "". Generally an indentation of two spaces per level of nesting is customary.

• Attribute delimiters will be unconditionally transformed to double-quotes if currently single-quotes. (I believe this is true of other answers as well.)

• Passing conformanceLevel : ConformanceLevel.Fragment allows strings containing sequences of XML fragments to be formatted.

• Other than ConformanceLevel.Fragment, the input XML string must be well-formed. If it is not, XmlReader will throw an exception.

Demo fiddle here.

.NET 2.0 ignoring name resolving, and with proper resource-disposal, indentation, preserve-whitespace and custom encoding:

public static string Beautify(System.Xml.XmlDocument doc)
{
    string strRetValue = null;
    System.Text.Encoding enc = System.Text.Encoding.UTF8;
    // enc = new System.Text.UTF8Encoding(false);

    System.Xml.XmlWriterSettings xmlWriterSettings = new System.Xml.XmlWriterSettings();
    xmlWriterSettings.Encoding = enc;
    xmlWriterSettings.Indent = true;
    xmlWriterSettings.IndentChars = "    ";
    xmlWriterSettings.NewLineChars = "\r\n";
    xmlWriterSettings.NewLineHandling = System.Xml.NewLineHandling.Replace;
    //xmlWriterSettings.OmitXmlDeclaration = true;
    xmlWriterSettings.ConformanceLevel = System.Xml.ConformanceLevel.Document;


    using (System.IO.MemoryStream ms = new System.IO.MemoryStream())
    {
        using (System.Xml.XmlWriter writer = System.Xml.XmlWriter.Create(ms, xmlWriterSettings))
        {
            doc.Save(writer);
            writer.Flush();
            ms.Flush();

            writer.Close();
        } // End Using writer

        ms.Position = 0;
        using (System.IO.StreamReader sr = new System.IO.StreamReader(ms, enc))
        {
            // Extract the text from the StreamReader.
            strRetValue = sr.ReadToEnd();

            sr.Close();
        } // End Using sr

        ms.Close();
    } // End Using ms


    /*
    System.Text.StringBuilder sb = new System.Text.StringBuilder(); // Always yields UTF-16, no matter the set encoding
    using (System.Xml.XmlWriter writer = System.Xml.XmlWriter.Create(sb, settings))
    {
        doc.Save(writer);
        writer.Close();
    } // End Using writer
    strRetValue = sb.ToString();
    sb.Length = 0;
    sb = null;
    */

    xmlWriterSettings = null;
    return strRetValue;
} // End Function Beautify

Usage:

System.Xml.XmlDocument xmlDoc = new System.Xml.XmlDocument();
xmlDoc.XmlResolver = null;
xmlDoc.PreserveWhitespace = true;
xmlDoc.Load("C:\Test.svg");
string SVG = Beautify(xmlDoc);

Check the following link: Format an XML file so it looks nice in C#

// Format the XML text.
StringWriter string_writer = new StringWriter();
XmlTextWriter xml_text_writer = new XmlTextWriter(string_writer);
xml_text_writer.Formatting = Formatting.Indented;
xml_document.WriteTo(xml_text_writer);

// Display the result.
txtResult.Text = string_writer.ToString();

Customizable Pretty XML output with UTF-8 XML declaration

The following class definition gives a simple method to convert an input XML string into formatted output XML with the xml declaration as UTF-8. It supports all the configuration options that the XmlWriterSettings class offers.

using System;
using System.Text;
using System.Xml;
using System.IO;

namespace CJBS.Demo
{
    /// <summary>
    /// Supports formatting for XML in a format that is easily human-readable.
    /// </summary>
    public static class PrettyXmlFormatter
    {

        /// <summary>
        /// Generates formatted UTF-8 XML for the content in the <paramref name="doc"/>
        /// </summary>
        /// <param name="doc">XmlDocument for which content will be returned as a formatted string</param>
        /// <returns>Formatted (indented) XML string</returns>
        public static string GetPrettyXml(XmlDocument doc)
        {
            // Configure how XML is to be formatted
            XmlWriterSettings settings = new XmlWriterSettings 
            {
                Indent = true
                , IndentChars = "  "
                , NewLineChars = System.Environment.NewLine
                , NewLineHandling = NewLineHandling.Replace
                //,NewLineOnAttributes = true
                //,OmitXmlDeclaration = false
            };

            // Use wrapper class that supports UTF-8 encoding
            StringWriterWithEncoding sw = new StringWriterWithEncoding(Encoding.UTF8);

            // Output formatted XML to StringWriter
            using (XmlWriter writer = XmlWriter.Create(sw, settings))
            {
                doc.Save(writer);
            }

            // Get formatted text from writer
            return sw.ToString();
        }



        /// <summary>
        /// Wrapper class around <see cref="StringWriter"/> that supports encoding.
        /// Attribution: http://stackoverflow.com/a/427737/3063884
        /// </summary>
        private sealed class StringWriterWithEncoding : StringWriter
        {
            private readonly Encoding encoding;

            /// <summary>
            /// Creates a new <see cref="PrettyXmlFormatter"/> with the specified encoding
            /// </summary>
            /// <param name="encoding"></param>
            public StringWriterWithEncoding(Encoding encoding)
            {
                this.encoding = encoding;
            }

            /// <summary>
            /// Encoding to use when dealing with text
            /// </summary>
            public override Encoding Encoding
            {
                get { return encoding; }
            }
        }
    }
}

Possibilities for further improvement:-

• An additional method GetPrettyXml(XmlDocument doc, XmlWriterSettings settings) could be created that allows the caller to customize the output.
• An additional method GetPrettyXml(String rawXml) could be added that supports parsing raw text, rather than have the client use the XmlDocument. In my case, I needed to manipulate the XML using the XmlDocument, hence I didn't add this.

Usage:

String myFormattedXml = null;
XmlDocument doc = new XmlDocument();
try
{
    doc.LoadXml(myRawXmlString);
    myFormattedXml = PrettyXmlFormatter.GetPrettyXml(doc);
}
catch(XmlException ex)
{
    // Failed to parse XML -- use original XML as formatted XML
    myFormattedXml = myRawXmlString;
}

if you load up the XMLDoc I'm pretty sure the .ToString() function posses an overload for this.

But is this for debugging? The reason that it is sent like that is to take up less space (i.e stripping unneccessary whitespace from the XML).

Hi why don't you just try this:

XmlDocument xmlDoc = new XmlDocument();
xmlDoc.PreserveWhitespace = false;
....
....
xmlDoc.Save(fileName);

PreserveWhitespace = false; that option can be used xml beautifier as well.