You read the old XML into an XmlDocument and either:
1) iterate through it via C# code and construct a new
   XmlDocument with what you want and store that to disk
or:
2) use XSLT to transform it to the new XML you want

Arne

This should be exactly what you're looking for:
http://sholliday.spaces.live.com/Blog/cns!A68482B9628A842A!148.entry

 I want to create a new XML file from another XML file. The original file will be stored on the hard drive and it is about 3mb. I do not need everything from the original XML file so the new one will be much smaller and easier to manage. I only need to do this when new data has been added to the original XML file. Here is a sample of what I have.

 Original XML file

 <movielist>
         <movie>
             <index>1</index>
             <title>Casino Royale</title>
             <cast>
                 <star>
                     <person>
                         <displayname>Daniel Craig</displayname>
                     </person>
                     <character>James Bond</character>
                 </star>
                 <star>
                     <person>
                         <displayname>Eva Green</displayname>
                     </person>
                     <character>Vesper Lynd</character>
                 </star>
             </cast>
         </movie>
         <movie>
             <index>2</index>
             <title>Spider-Man</title>
             <cast>
                 <star>
                     <person>
                         <displayname>Tobey Maguire</displayname>
                     </person>
                     <character>Spider-Man/Peter Parker</character>
                 </star>
                 <star>
                     <person>
                         <displayname>Kirsten Dunst</displayname>
                     </person>
                     <character>Mary Jane Watson</character>
                 </star>
                 <star>
                     <person>
                         <displayname>Willem Dafoe</displayname>
                     </person>
                     <character>Green Goblin/Norman Osborn</character>
                 </star>                
             </cast>
         </movie>
 </movielist>

 Below is how I want the new file to look by combining the displayname and character in the cast section.

 New XML file

 <movielist>
         <movie>
             <index>1</index>
             <title>Casino Royale</title>
             <cast1>Daniel Craig - James Bond</cast1>
             <cast2>Eva Green - Vesper Lynd</cast2>
         </movie>
         <movie>
             <index>2</index>
             <title>Spider-Man</title>
             <cast1>Tobey Maguire - Spider-Man/Peter Parker</cast1>
             <cast2>Kirsten Dunst - Mary Jane Watson</cast2>
             <cast3>Willem Dafoe - Green Goblin/Norman Osborn</cast3>
         </movie>
 </movielist>  

 Any help will be greatly appreciated

 Thanks
 Mary

The link is in VB, but you should be able to figure it out. You should look
at the XMLDocument read section.

http://developer.yahoo.com/dotnet/howto-xml_vb.html

You should be able to look at the two links and figure out how to read the
XML and how to write out the XML that you need using XML Documents.

http://support.softartisans.com/kbview_675.aspx

I have been into XML here recently on a project. I now know more about XML
and  SOAP XML Web Services than I ever even cared to know. :)

Other posts have mentioned the options... just to mention that DOM
models (such as XmlDocument) can (depending on the data) take
significantly more memory that the original data-file, which might be
worth considering since your original file is not trivial (3Mb).

XmlDocument presents a simple model, so perhaps just benchmark it?
Load the data into XmlDocument (.Load) and see how the memory usage
jumps? If it is significant, XmlReader and XmlWriter might be a good
way to go.

This would also be a simple xslt operation, which could be useful as I
believe this uses (if given a stream or XmlReader) the more light-
weight readonly DOM model (the class name escapes me at the moment...)

Marc

What will be the best way to change the cast section?

OLD XML
<cast>
   <star>
       <person>
           <displayname>Daniel Craig</displayname>
       </person>
       <character>James Bond</character>
   </star>
   <star>
       <person>
           <displayname>Eva Green</displayname>
       </person>
       <character>Vesper Lynd</character>
   </star>
</cast>

NEW XML
<cast1>Daniel Craig - James Bond</cast1>
<cast2>Eva Green - Vesper Lynd</cast2>

I am currently using the following code.

XmlDocument doc = new XmlDocument();
doc.Load("old.xml");
XmlTextWriter writer = new XmlTextWriter("new.xml", null);
writer.Formatting = Formatting.Indented;
writer.WriteStartElement("movielist");
               
XmlNodeList nodes = doc.SelectNodes("movielist/movie");

foreach (XmlNode node in nodes)
{
writer.WriteStartElement("movie");

XmlNode titleNode = node.SelectSingleNode("title");
writer.WriteElementString("title", titleNode.InnerText);

XmlNode indexNode = node.SelectSingleNode("index");
writer.WriteElementString("index", indexNode.InnerText);
}

writer.WriteEndElement();
writer.WriteEndElement();
writer.Close();

Thanks for the replies
Mary

 I want to create a new XML file from another XML file. The original file will be stored on the hard drive and it is about 3mb. I do not need everything from the original XML file so the new one will be much smaller and easier to manage. I only need to do this when new data has been added to the original XML file. Here is a sample of what I have.

 Original XML file

 <movielist>
         <movie>
             <index>1</index>
             <title>Casino Royale</title>
             <cast>
                 <star>
                     <person>
                         <displayname>Daniel Craig</displayname>
                     </person>
                     <character>James Bond</character>
                 </star>
                 <star>
                     <person>
                         <displayname>Eva Green</displayname>
                     </person>
                     <character>Vesper Lynd</character>
                 </star>
             </cast>
         </movie>
         <movie>
             <index>2</index>
             <title>Spider-Man</title>
             <cast>
                 <star>
                     <person>
                         <displayname>Tobey Maguire</displayname>
                     </person>
                     <character>Spider-Man/Peter Parker</character>
                 </star>
                 <star>
                     <person>
                         <displayname>Kirsten Dunst</displayname>
                     </person>
                     <character>Mary Jane Watson</character>
                 </star>
                 <star>
                     <person>
                         <displayname>Willem Dafoe</displayname>
                     </person>
                     <character>Green Goblin/Norman Osborn</character>
                 </star>                
             </cast>
         </movie>
 </movielist>

 Below is how I want the new file to look by combining the displayname and character in the cast section.

 New XML file

 <movielist>
         <movie>
             <index>1</index>
             <title>Casino Royale</title>
             <cast1>Daniel Craig - James Bond</cast1>
             <cast2>Eva Green - Vesper Lynd</cast2>
         </movie>
         <movie>
             <index>2</index>
             <title>Spider-Man</title>
             <cast1>Tobey Maguire - Spider-Man/Peter Parker</cast1>
             <cast2>Kirsten Dunst - Mary Jane Watson</cast2>
             <cast3>Willem Dafoe - Green Goblin/Norman Osborn</cast3>
         </movie>
 </movielist>  

 Any help will be greatly appreciated

 Thanks
 Mary