Comparing XML string with different formats

Question

I need to compare 2 xml strings where the formatting may be different. The approach is to use the XmlWriterSettings to format both strings and compare the formatted result:

public static class XmlHelper
{
 public static string FormatXml(string xml)
 {
 try
 {
 var stringBuilder = new StringBuilder();
 var element = XDocument.Parse(xml);
 var settings = new XmlWriterSettings();
 settings.OmitXmlDeclaration = true;
 settings.Indent = true;
 settings.IndentChars = " ";
 settings.NewLineChars = Environment.NewLine;
 settings.NewLineOnAttributes = false;
 settings.NewLineHandling = NewLineHandling.Replace;
 using (var xmlWriter = XmlWriter.Create(stringBuilder, settings))
 element.Save(xmlWriter);
 return stringBuilder.ToString();
 }
 catch (Exception ex)
 {
 Logger.Error("Unable to format XML: '" + xml + "'", ex);
 return xml;
 }
 }
 public static bool CompareXml(string xmlA, string xmlB)
 {
 if (xmlA == null && xmlB == null)
 return true;
 if (xmlA == null || xmlB == null)
 return false;
 var xmlFormattedA = FormatXml(xmlA);
 var xmlFormattedB = FormatXml(xmlB);
 return xmlFormattedA.Equals(xmlFormattedB, StringComparison.InvariantCultureIgnoreCase);
 }
}

My questions are:

• Do you see any problems with that approach?
• Is there a simpler way to accomplish that kind of comparison?

Answer 1

Googling for xml compare c# produces countless results so I just review this code without suggesting anything alternative.

---

settings.IndentChars = " ";

I find new string(' ', 3) is easier to understand then three (?) spaces.

---

 if (xmlA == null && xmlB == null)
 return true;

This is questionable. I'd say it should be false.

---

var settings = new XmlWriterSettings();
settings.OmitXmlDeclaration = true;

Don't you like object initializers?

var settings = new XmlWriterSettings
{
 OmitXmlDeclaration = true
};

• JanDotNet: Thanks for the feedback. a) agree (they are actual 2 spaces ;)) b) Yes, that is questionable (and it is very unlikely that the case occurs someday)... however, string.Equals(null, null) is true, therefore I think the result should be true as well . c) I like it too... changed the impl. :)