File locking and access using locks or mutex or monitor?

[Gery D. Dorazio]

Here is some code to open a file with exclusive access for the purpose of
modifying it.

FileStream fstrm = new FileStream(inputFileName, FileMode.OpenOrCreate,
FileAccess.ReadWrite, FileShare.None);
DataSet ds = new DataSet("MyDataSet");
ds.ReadXml(fstrm);
....edit a row here...
ds.AcceptChanges();
fstrm.Seek(0, SeekOrigin.Begin);
ds.WriteXml(fstrm, XmlWriteMode.IgnoreSchema);
fstrm.Close();
This works well except when there are multiple accesses to the same input
file and one is in the middle of changing it.... an access failure occurs.
So I set of trying to determine how to use a lock, or monitor, or mutex, or
async IO...so that others have to wait until the file is available before
they can access it rather than fail with an access failure. This is what I
am trying to figure out how to do.

The design criteria is that the access mechanism is designed within one
class. But this class is to be able to provide controlled IO to multiple
files.

Can this be done with the Monitor, Mutex, AutoResetEvent, or
ManualResetEvent or some other synchronization object?

Thanks,
Gery

--
Gery D. Dorazio
Development Engineer

EnQue Corporation
1334 Queens Road
Charlotte, NC 28207
[phone]

[Angel J. Hernández M.]

Hi there... There are a couple of good articles that explain this subject in
depth.

http://msdn.microsoft.com/msdnmag/is...asicinstincts/
http://msdn.microsoft.com/msdnmag/is...asicinstincts/

Hope this may help you,

Regards,
--
Angel J. Hernández M.
MCP - MCAD - MCSD - MCDBA
http://groups.msn.com/desarrolladoresmiranda
http://www.consein.com
"Gery D. Dorazio" <gd******@enque.net> escribió en el mensaje
news:Os**************@TK2MSFTNGP09.phx.gbl...

Here is some code to open a file with exclusive access for the purpose of
modifying it.

FileStream fstrm = new FileStream(inputFileName, FileMode.OpenOrCreate,
FileAccess.ReadWrite, FileShare.None);
DataSet ds = new DataSet("MyDataSet");
ds.ReadXml(fstrm);
...edit a row here...
ds.AcceptChanges();
fstrm.Seek(0, SeekOrigin.Begin);
ds.WriteXml(fstrm, XmlWriteMode.IgnoreSchema);
fstrm.Close();
This works well except when there are multiple accesses to the same input
file and one is in the middle of changing it.... an access failure occurs.
So I set of trying to determine how to use a lock, or monitor, or mutex,
or async IO...so that others have to wait until the file is available
before they can access it rather than fail with an access failure. This is
what I am trying to figure out how to do.

The design criteria is that the access mechanism is designed within one
class. But this class is to be able to provide controlled IO to multiple
files.

Can this be done with the Monitor, Mutex, AutoResetEvent, or
ManualResetEvent or some other synchronization object?

Thanks,
Gery

--
Gery D. Dorazio
Development Engineer

EnQue Corporation
1334 Queens Road
Charlotte, NC 28207
[phone]