Re: file open check - C# Discussion Boards

26-Jun-05 23:29

This question has been asked here a gazillion times, so please use the search function before posting...

Regards,
mav

file open check

syseca_challenge26-Jun-05 22:25

26-Jun-05 22:25

Hi
I save my documents in a database. While opening them, I make a copy on the local hd and open them. But how can I know, when the user has finished with the changes and closed the document, so I can save them back to the db?

Is there something like a file open check?

At least the office programms have kind of a lock, so only one user can open the document. Can I use that - and if yes, how?

Thank you

Adrian

mav.northwind26-Jun-05 22:53

26-Jun-05 22:53

Hi!

There's no general "data from this file still in use" flag.
As long as a file has been opened by an application, Windows will know that the file is open, but usually an application will close the file as soon as it's been read. While you're working with the data, the file is closed, so there's no general way to know when you've finished manipulating the data.

Each application has to decide for itself if and how to maintain file locks.

For Office documents there might be properties to find out the user who has opened a document recently, but I'm not sure.
For other documents each application will most likely behave differently.

Regards,
mav

V.27-Jun-05 0:46

27-Jun-05 0:46

I can think of following workaround
Create a copy of your current file in memory, then try to delete it, (see MSDN File.Delete Function) if it throws the IOException, the file is still in use Wink | ;-)

.
if it's deleted, write your in-memory version to db.

Good luck.

No hurries, no worries.

mav.northwind27-Jun-05 1:03

27-Jun-05 1:03

That won't work!
Imagine a plain text file that's being edited with Notepad.
The file will only be in use while Notepad actually loads it. This takes a fraction of a second, after that your "workaround" would save the file back to the DB, albeit the user didn't even have a chance to modify the text or save the changed file!

mav

syseca_challenge27-Jun-05 1:31

27-Jun-05 1:31

Im checking a workaround by watching the process I had started. It doesn't work always, because most of the programs, like word, don't create a new process when they'r already open.

V.27-Jun-05 1:33

27-Jun-05 1:33

ok tnx, but there should be a way for checking if a file is in use, no?

No hurries, no worries.

mav.northwind27-Jun-05 1:51

27-Jun-05 1:51

There is a check, and usually the easiest way to check is to try to open a file exclusively. If this fails, then usually another process has the file in use.

But the main point is that "file is in use" is not the same as "the data inside the file is being modified".

mav

syseca_challenge27-Jun-05 1:55

27-Jun-05 1:55

The process watcher version doesn't work neither. The problem is, that many programs immediately delecate the file to another process and stop the first one. By office programs I even never get the process. Frown | :-(

mav.northwind27-Jun-05 1:56

27-Jun-05 1:56

That's what I'm saying. There is no general way, sorry.

mav

syseca_challenge27-Jun-05 2:40

Re: .net 2005 importing!!!!

27-Jun-05 2:40

Thank you a lot.

.net 2005 importing!!!!

innocent7326-Jun-05 20:49

innocent73

26-Jun-05 20:49

Hello,
is it possible to use datagrid component of .net 2005 in .net 2003?
if yes, please tell me how??

Dave Kreskowiak27-Jun-05 9:24

Dave Kreskowiak

27-Jun-05 9:24

The short answer is No, that DataGrid requires 2005 to run. The 2003 compilers will not work with the 2005 .NET Framework. You'd have to write a remoting wrapper around the DataGrid class. The more I think about it, the uglier it gets.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Calling C# from Managed C++

wdli26-Jun-05 19:25

wdli

26-Jun-05 19:25

Hello Everyone:

I have posted the same question in managed C++ board.

This is my problem:

I have C# project compiled as a DLL. The C# class is defined as:

public Cs_Class
{
String name;
public Cs_Class(String n)
{ name = n; }

....
}

I have another MC++ project that uses the DLL. The MC++ class is defined as:

public Cpp_Class
{
....
void Test(String* testStr)
{
//Create the c# class
//
Cs_Class* c = new Cs_Class(testStr);
}

}

The compilation/linking was fine. I then encountered a run-time exception:

System.MissingMethodException: Method not found: Cs_Class..ctor(System.String)...

Strangly enough, if I took out the String parameter in Cs_Class constructor and not pass in String* in MC++ class when constructing the Cs_Class object, then everything was fine.

Why??

Thanks in advance.

David

Re: Calling C# from Managed C++

Fahaad Yogalivia26-Jun-05 20:58

Fahaad Yogalivia

26-Jun-05 20:58

To hence forth the problem is to dematerialize the occasion of being interpeticular of yomessing

Re: Calling C# from Managed C++

mav.northwind27-Jun-05 2:48

Re: Calling C# from Managed C++

27-Jun-05 2:48

I'm not a native english speaker either, but this seems to come from a translation program and has completely lost its meaning in the process of translation.
Am I correct? And if I am, which translation service was used and what was the original phrase?

:->
mav

wdli27-Jun-05 8:30

wdli

27-Jun-05 8:30

Hello,
I am not sure I understand what you meant here. Can you explain your point in plain English? Thanks

compile a C# class file from a procees in code

dilsudharaka26-Jun-05 18:27

dilsudharaka

26-Jun-05 18:27

I want to compile a existing c# class file, inside another program. I used the Following code. But it does not give any outputs. can you tell me a correct way to do this. thanks.

Process pr = new Process();
pr.StartInfo.FileName = "csc.exe";
string filePath = "D:\\Dilan Projects\\Application3\\LabelWriter.cs";
pr.StartInfo.Arguments ="/out:cl_labelservice.dll /t:library " + filePath;
pr.Start();

this code not working.

Re: compile a C# class file from a procees in code

Christian Graus26-Jun-05 18:36

Christian Graus

26-Jun-05 18:36

'not working' is kind of enigmatic. What's going wrong ? Best guess - you need to specify a path to csc.exe

Christian Graus - Microsoft MVP - C++

Re: compile a C# class file from a procees in code

S. Senthil Kumar26-Jun-05 19:19

S. Senthil Kumar

26-Jun-05 19:19

Do you see a console window opening up? Did you try redirecting standard output and error to see what's actually going on?

Regards
Senthil
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Re: compile a C# class file from a procees in code

mav.northwind26-Jun-05 20:39