How to find if file is already open.

Question

Hi,

I'am storing word documents content in DB. Then i'm reading the contents of the file and placing it in isolated store for application and user.using System.Diagnotics. Process.Start(physicalfilepath) i'm trying to start the process. The document opens. My requirement is if the document is already open i need to show a message to user that file is already open. How to  achieve this functionality. Kindly advice.

Regards,

Megarekaa.

Answer 1

A dirty way is to try and open it:

try

{

using (FileStream fs = new FileStream("filename.TXT",FileMode.Open))

{

}

}

catch (IOException e)

{

MessageBox.Show("File is allready open!");

}

Answer 2

You can use the WMI class CIM_LogicalFile and check the InUseCount. It gives the number of "file opens" that are currently active against the file.

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Answer 3

Or alternatively:

protected virtual bool IsFileLocked(FileInfo file)
{
    FileStream stream = null;

    try
    {
        stream = file.Open(FileMode.Open, FileAccess.ReadWrite, FileShare.None);
    }
    catch (IOException)
    {
        //the file is unavailable because it is:
        //still being written to
        //or being processed by another thread
        //or does not exist (has already been processed)
        return true;
    }
    finally
    {
        if (stream != null)
            stream.Close();
    }

    //file is not locked
    return false;
}

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John Grove, Senior Software Engineer http://www.digitizedschematic.com/

Answer 4

I don't know how Mark Russinovich from SysInternals did it, but you can use this handle.exe as an external tool to find out: http://technet.microsoft.com/en-us/sysinternals/bb896655