c# - Detecting Xml namespace fast -

This may be a very trivial problem that I am trying to solve, but I'm sure There is a better way. So please be easy for me.

I have a bunch of XSD files that are internal to our application, we have around 20-30 XML files that implement a dataset based on those XSDs. Some XML files are small (& lt; 100Kb), with more than 10 MB to 3-4 MB.

I need to know that where these XML files are available (like some) based on intellisense XSD, its implementation is not an issue - another developer has written the code for it.

But I'm not sure the best (and the fastest!) Method to locate the name space is without the use of XmlDocument which parses full).

I am using C # 3.5 and documents come in the form of a stream (some are remote files). All files * .xml (I can find out that this extension was based) but unfortunately XML namespace is the only way.

I have tried XmlDocument right now but I disable it and slow down because waiting for parsing large documents (even 100Kb docs).

  public string GetNamespaceForDocument (stream document);  

Something like the above is my method signature - contains the string for "content" in overload What would be a RegEx (compiled) pattern good?

How does the Visual Studio manage so efficiently? Another college has asked me to find a fast xml parser in C / C ++, parsing content and a stub that returns netspace back to its net as.net, is it a good idea is?