Write to same text file from two different sources

[suprsnipes]

Hi,

I am using the following method to write to a text file and would like to know what I need to change to be able to write to the same text file without seeing 'the process cannot access the file because it is being used by another process' error message.

using System.IO;

File.AppendAllText()

Regards,
suprsnipes

[NinjaTrader_Bertrand]

Do you mean writing to the same txt file from two or more different script / strategies? With no cross communication this would not be easily possible, since you would need to implement a mutex / lock concept to be able to ensure no concurrent access would be attempted.

[suprsnipes]

Hi Bertrand,

Thanks for your suggestions I'm thinking that I may need to try and achieve something less difficult at first. What about allowing the text file that I am writing to access for another process to read?

Regards,
suprsnipes

[sledge]

Hi Bertrand,

Thanks for your suggestions I'm thinking that I may need to try and achieve something less difficult at first. What about allowing the text file that I am writing to access for another process to read?

Regards,
suprsnipes

Windows OS does not like this. I do not think this has changed post Vista.

I havent done excessive testing, but things are locked unless the original process closes the file, which is what you are hitting.

Closing and reopening the file will be a performance hit for sure.

Are you sure you need to do this?

[koganam]

Hi,

I am using the following method to write to a text file and would like to know what I need to change to be able to write to the same text file without seeing 'the process cannot access the file because it is being used by another process' error message.

using System.IO;
 
File.AppendAllText()

Regards,
suprsnipes

According to the description on http://msdn.microsoft.com/en-us/libr...(v=vs.90).aspx, the method "opens, writes and closes" the target file. That implies that eventually, the file lock will be released.

It seems that you will have to write a loop that uses a Try/Catch block to keep trying until it succeeds.

Otherwise, you might try opening the file with the requisite share permissions. ref: http://msdn.microsoft.com/en-us/libr...(v=vs.90).aspx

[gonzalolandin]

Also Interested

Hello,
I am also interested in this issue. I am trying to write in the same file from multiple sources (the same indicator in multiple time period).
Thanks for your help.

[Zeos6]

Hi,

The issue here seems to be multiple sources, and possibly concurrent access. The fastest way of synchronizing access between processes is to use Mutexes / Semaphores. Have you tried this approach?

[suprsnipes]

Hi,

In relation to the following reply mentioned at the bottom is a link to the Microsoft site with information on how to allow read access to a file whilst it is also being used by another process titled 'FileShare Enumeration'. How would you incorporate this into existing code that is using File.AppendAllText?

According to the description on http://msdn.microsoft.com/en-us/libr...(v=vs.90).aspx, the method "opens, writes and closes" the target file. That implies that eventually, the file lock will be released.

It seems that you will have to write a loop that uses a Try/Catch block to keep trying until it succeeds.

Otherwise, you might try opening the file with the requisite share permissions. ref: http://msdn.microsoft.com/en-us/libr...(v=vs.90).aspx

Regards,
suprsnipes

[koganam]

Hi,

In relation to the following reply mentioned at the bottom is a link to the Microsoft site with information on how to allow read access to a file whilst it is also being used by another process titled 'FileShare Enumeration'. How would you incorporate this into existing code that is using File.AppendAllText?



Regards,
suprsnipes

We would have to see how you have written the code before we can say how it can be modified.

[sledge]

We would have to see how you have written the code before we can say how it can be modified.

Pretty obvious from the MS spec posted earlier. Thanks!

[koganam]

Pretty obvious from the MS spec posted earlier. Thanks!

Yes, but he wants to know how to use it in HIS code, so we need to see his code.