XmlReader,XmlWriter - concat xmlFiles using streams

Question

I have some procedures which return xml files.

Is it possible to concat many xml files using only streams?

something like this:

     XmlWriter writer = XmlWriter.Create(sb,settings)
     {

          foreach(var cmd in XmlFiles)
          {
             using (XmlReader r = cmd.ExecuteXmlReader())
             {
                  while (r.Read())
                  {
                         string xml = r.ReadOuterXml();
                         writer.WriteRaw(xml);
                   }
              }
          }

     }

I need do this without using string because i have to deal with big files.

Answer 1

If you don't want to use strings then why do you use ReadOuterXml and WriteRaw? There is a method WriteNode that consumes an XmlReader passed in, so doing e.g.

        string[] inputFiles = { "XMLFile1.xml", "XMLFile2.xml" };

        using (XmlWriter xw = XmlWriter.Create("result.xml"))
        {
            xw.WriteStartDocument();
            xw.WriteStartElement("root");
            foreach (string inputFile in inputFiles)
            {
                using (XmlReader xr = XmlReader.Create(inputFile))
                {
                    xr.MoveToContent();
                    xw.WriteNode(xr, true);
                }
            }
            xw.WriteEndElement();
            xw.WriteEndDocument();

would create a new XML document with a root element wrapping the contents of the two XML files.

In your code you could therefore use

      foreach(var cmd in XmlFiles)
      {
         using (XmlReader r = cmd.ExecuteXmlReader())
         {
              r.MoveToContent();
              writer.WriteNode(r, false);
          }
      }

as long as you make sure you output a root element wrapper (or you use an XmlWriter with XmlWriterSettings and ConformanceLevel.Fragment).