Compares 2 XMl documents and spits out the merged file with additions, updates and deleted nodes removed.

XML Diff

public void CompareTwoXmlFilesInMemory()
		{
			using (MemoryStream diffgram = new MemoryStream())
			{
				XmlTextWriter diffgramWriter = new XmlTextWriter(new StreamWriter(diffgram));
				XmlDiff xmldiff =
					new XmlDiff(XmlDiffOptions.IgnoreChildOrder | XmlDiffOptions.IgnoreNamespaces | XmlDiffOptions.IgnorePrefixes);

				bool identical = xmldiff.Compare(@"appconfig2.xml", @"appconfig3.xml", false, diffgramWriter);

				Assert.IsFalse(identical);

				//Resets the position to 0 so we can read.
				diffgram.Position = 0;
				PatchUp(@"appconfig3.xml", diffgram, "test.xml");
			}
		}

		public void PatchUp(string originalFile, Stream diffGram, string outputFile)
		{
			XmlDocument sourceDoc = new XmlDocument();
			sourceDoc.Load(originalFile);

			XmlTextReader diffgramReader = new XmlTextReader(diffGram);

			XmlPatch xmlPatch = new XmlPatch();
			xmlPatch.Patch(sourceDoc, diffgramReader);

			XmlTextWriter output = new XmlTextWriter(outputFile, Encoding.Unicode);
			sourceDoc.PreserveWhitespace = true;
			sourceDoc.Save(output);
			output.Close();
		}