Reading a file without causing IOException on 3rd party program

Question

I'm reading a file which is periodically being written to by a 3rd party program. Im reading using the below FileStream:

using (FileStream fs = new FileStream(
                         FullPath,
                         FileMode.Open,
                         FileAccess.Read,
                         FileShare.ReadWrite))

However the 3rd party program is writing to the file but is using the FileShare.None

So occasionally I've got the file open for reading when the 3rd party program tries to open the file with exclusive access but fails.

How can I read this file without causing problems for the 3rd party program? I wouldn't mind releasing my read to give priority to another application. Any way to do this?

Answer 1

What you want to do is monitor for process creation notifications, and when you see the specific process come into existence, you will want to get out of its way.

IWbemServices::ExecNotificationQuery

Here are some some additional details off of MSDN. Here is also a CodeProject: Process Information and Notifications using WMI

Answer 2

If this 3rd party proccess (.exe, windows service, web app, etc.) ever stops, you could access the file when that happens, if it never stops or it's impossible to tell when it will run, you could do a copy this file as soon as you turn on the server.

This will be valid or not depending on the nature of your app and the other one, and on how often you need to read this file.