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We'll need to know a lot more about your app before we can suggest anything. What else did you code do? Are you sure you're freeing all of your unmanaged resources? Are you doing any custom drawing of an graphics or controls? ... ... ...
Dave Kreskowiak
Microsoft MVP - Visual Basic
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There is no built-in way to handle concurrency issues - you must do a number of things for example:
1) Add a timestamp column to each database table
2) When loading a row update/get the timestamp
3) when saving a row compare client-side timestamp with current database timestamp
4) If they differ reject the update (or take appropriate action)
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The subject line you used IS useless. Everyone who comes here is looking for help, so putting "Help me!" in the subject line doesn't really make you stand out at all.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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PREMSONBABY wrote: please dont tell that it is not possible or useless
Where exactly did I say waht you are trying to do was "useless or impossible"?? I said your subject line was useless for the reason Dave K described. We also have an SQL / ADO.NET forum here which would have been a better place for this post.
PREMSONBABY wrote: if u dont know something
I know more than something sonny. I have dealt with this particular issue (db concurrency) many many times and I gave you one (of many) solution to the problem. Dave gave a second.
A simple thankyou would have been appreciated!
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PREMSONBABY wrote: i want to know is there any changes in the sql table, in the database.
The only way to tell, and even this isn't perfect, is to load another dataset with the table your updating, then compare each record to what you have. Any differences will tell you that the data has changed. But, the data can change WHILE you're doing the compare.
If you're going to use a disconnected approach like this, you'll just have to deal with the fact that the "last write wins". The last client to write to the database overwrites any and all other changes.
Now, under SQL Server, there is what's called Notification Services. This allows your application to subscribe to certain events that occur in your database. SQL Server will then notify you when these events happen and your code can take appropriate action.
SQL Server Notification Services[^]
Dave Kreskowiak
Microsoft MVP - Visual Basic
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I don't have any public domain NS code I can share. But, there are TONS of examples in the documentation for it.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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hi , i use from from Shockwave Flash Component in visual studio 2003 without any problem but in VS 2005 whene i want add Shockwave Flash Component to a form,VS2005 show a Error and say i should register "Shockwave Flash Component". please help me.
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I've never heard of the problem. You might want to try reinstalling the Flash Player or see if there is any information on Adobe's support board.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Dear Dave Kreskowiak
My problem solved. when i want add "Shckwave Flash Component" to my windows form in VS 2005, this error will create : "Failed to import the ActiveX control. Please ensure it is properly registered".
see here for soloution : http://www.bleepingcomputer.com/forums/topic66144.html
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i hv a grid where one field is "Date" there i hv usd one htmlinputtexbx and a js calendar and what i want tht when a user will click on edit button the date lable (in items) should be cnvrted into the calendr now my problem is that ---- i am able to display the calendar button bt when a user clicks on the calendar button he doesnt get the calendar plz help me
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You might want to try this question in the ASP.NET Forum.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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hi
i'm trying to write a code for an application. this app will be installed on two or more computers and i want that the changes on the app on a computer will occur on other comp. at the same time. for example when a checkbox is checked on a comp., at the same time, the checkbox on other comp. will be checked.
i don't know can i explain the case but i need any help.
i think i must use sockets but how 
thanx
WoR
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It could be done using sockets or .NET Remoting. But, you have to implement some kind of command system in your app that can respond to these changes being made on the other instance. This is going to be a LARGE part of your project.
Why are you doing this? I can't see any possible reason that you would want to this...
Dave Kreskowiak
Microsoft MVP - Visual Basic
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First, thanks for the answer. It was just an example. Actually i want to develop an app that using a dataset. And this dataset will save entries that i entered with a form for entering data. This app will be installed on another comp and when we enter data, we would see the entries simultaneously.
I think this is a kind of an instant messagging.
Another idea is using xml web services. Is this suitable for the case? Or is the remoting the answer?
thanks again.
WofR
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Remoting is probably going to be the best answer. Instant messaging is only a small part of the system you want to put together.
IM only sneds a message to another client. The client doesn't have to worry about which control to modify and how to modify it. THIS is the complexity you're adding, and you're adding a LOT of it. Your biggest problem is going to be concurrency. What if two people are entering something in the same field at the same time? Who wins and why? This is what you must deal with. Messaging is easy compared to this.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Hi,
I am working with datagrid Winform (NET 1.1) and binding it with datatable.
I manually update the datatable from other datatable if the item value is change. After update it's value I want manually change the cell forecolor be blue if new value is greater or red if less than
Is there a way to do that? Thx
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Hi Dave,
Thanks for your link info.
I tried it and got the solution.
Thanks again
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I have USB devise that connected to HID in windows xp,
can i use the HID class to read data input from the device?
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If it uses a HID-based driver, then yes, but how you do it depends on the driver and the functionality that it exposes.
You can find an example of doing something like this here[^]. There's also more resources on The HID Page[^].
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Hi,
i am working on visual basic.can anybody help to creat a dynamic forms using the loop.
Thanks in advance
Ashok Vakkala
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What do you mean by "dynamic forms"? Creating new instances of a Form? Creating controls at runtime? What?
Dave Kreskowiak
Microsoft MVP - Visual Basic
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