How to detect that a file has been altered

[wduty]

I often see in programs (such as visual studio) a prompt indicating that a file which you have open has been modified by another user and whether or not you want to reload it. How would you go about doing this?

I usually use CreateFile for windows programs to read/write files, but I usually close the handle immediately after either reading or writing. I'm guesssing that I might have to open the file with FILE_SHARE_READ and FILE_SHARE_WRITE and then hang on to the handle and somehow monitor it for changes(?). Or perhaps there one or more of the access flags has to be set? Maybe a thread to monitor the handle or file state?

Anyone ever done this?
--Will Duty
wduty@radicalfringe.com

 

[Cagliostro]

You should implement some interfaces as IPersist*. When the function IPersist*.IsDirty() returns true, you should reaload it. There are also some interfaces what contains in the name *Sink*. This interface notify VisualStudio what something are changed. John Fill

ivfmd@mail.md

 

[Gorecki]

Most independent method is to check keeping the file date/time stamp. Using something like the WM_ACTIVATE or other messages to tell it to check the file again, your desired processes acting from there.

 

[chiph]

wduty -

Take a look at the change notification API calls:

FindFirstChangeNotification
FindNextChangeNotification
FindCloseChangeNotification

Chip H.

 

[Gorecki]

Dim fs, f, f1, fc
Set fs = CreateObject("Scripting.FileSystemObject&quot
Set f = fs.GetFolder(folderspec)
Set fc = f.Files
For Each f1 in fc

'Create a tag here adding the path to the file as the browser sees it.
Response.Write &quot;<A href=&quot; & f1.name & &quot;....>&quot; & f1.name & &quot;</a>&quot;
Next

Play with it and write to the browser until you get it correctly. Also remember the file needs to be available to the browser (

http://wwwroot+).

 

[Gorecki]

Opps, the last post went to the wrong forum..sorry

 

[wduty]

whoa! Thanks for all the responses! I will look at the different approaches and see which best suits what I am doing.
--Will Duty
wduty@radicalfringe.com