Do you want to canonicalize the xml? See http://www.w3.org/TR/xml-c14n for 
more info on canonicalization.

- If you do not need to canonicalize the xml just feed it to digest method 
without even using MSXML.
- If you do need to canonicalize the xml then you have to write your own 
canonicalizer in SAX writer interfaces (ISAXContentHandler etc) and then 
feed the resulting stream to the digest method. Of course it is easier to 
say than to implement this. Microsoft does not provide native canonicalizer 
however there is one in .Net.

Please do not use msxml4 any more you really should be using msxml6 and it 
can be downloaded from 
http://www.microsoft.com/downloads/details.aspx?FamilyID=993C0BCF-3BCF-4009-BE21-27E85E1857B1&displaylang=en

The question of why I load a 20 MB file and IE ends up using 1GB question 
coming up many times (with different numbers :) ). And the answer is under 
the covers IE uses MSXML XML mimeviewer to render the xml to the IE client. 
Rendering is done by first loading the input xml to dom document. Usually, 
you would see 10x-20x the size increase depending of the number of the 
nodes, node to text ratio etc. After that it uses 'default' xslt 
transformation to generate a html file on the file so IE can render it 
correctly. Resulting html will be proportional to the number of nodes in 
original xml. And then IE loads it to IE DOM (not xml dom) in the end 20MB 
file become 1GB. To see that you can use msxsl.exe to transform the input 
xml using msxml3.dll's embeded stylesheet and create an html file and load 
it to IE.
You can load msxsl.exe from 
http://www.microsoft.com/downloads/details.aspx?FamilyID=2fb55371-c94e-4373-b0e9-db4816552e41&DisplayLang=en

-- 
Regards,
- Umut Alev [MSFT]

This email sent from a machine running Vista RTM.


"fruitfruit.com" <no_email@f...> wrote in message 
news:1E9FB0B1-37B9-48F9-809E-4E3740DF2A9F@m......
> Hi,
> I have a XML file about 20MB. When loaded it in IE, it takes several 
> minutes
> and more than 1G memory. MSXML4.0 is used to create this file, it takes 
> about
> 100MB memory during creation. Now I want to add XML digest to this XML 
> file.
> I have looked at http://www.aleksey.com/xmlsec/ and worried of the
> performance. The XMLSec library needs to parse XML before generating 
> digest,
> this may take too long time. Has anybody used XML Digest on large XML file
> before?
>