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Run a process from a FileSystemWatcher only once ...how?

Hi,
I have a curious problem. I am using a WindowsService with a FileSystemWatcher component that does the following: as soon as I send a bmp image to folder A, the bmp image is converted to a gif image and saved in a folder B, from where the image is sent to a bluetooth device. The problem that I am encountering is that the process of sending the gif image is not executed only once...it keeps on running until I stop it. (i.e. the image is sent more than once). Why is that so? What can I do to make it run only once?
Below is what i've done:
_____________________________________________
Private Sub FileSystemWatcher1_Changed(ByVal sender As System.Object, ByVal e As System.IO.FileSystemEventArgs) Handles FileSystemWatcher1.Changed

Dim imgFile As System.Drawing.Image = System.Drawing.Image.FromFile("C:\FolderA\image.bmp")
imgFile.Save("C:\FolderB\image.gif", System.Drawing.Imaging.ImageFormat.Gif)

Process.Start("Folder B") 'to open folder where there is the gif image

SendKeys.SendWait(" ")
SendKeys.SendWait("%fn")
SendKeys.SendWait("{RIGHT}")
SendKeys.SendWait("{ENTER}")
SendKeys.SendWait("%fc")

'''''(I had to use SendKeys to send the image to a bluetooth device, because other
'''''methods, such as the Environment.SpecialFolder.SendTo... , did not work)

Application.Exit() 'I tried this to exit process, but it did not work
Application.ExitThread() 'this did not work either

End Sub
___________________________________________________________________

How can I make the above process run only once and exit?
Thanks in advance for your help.

graye

Yeah, I've had the same problems.... My solution (which is anything but elegant!) is to create a timestamp and check for repeat calls...

Here is a chunk of code from my OnChange event handler....

Static LastRun As Date

System.Threading.Thread.Sleep(1000)
If DateDiff(DateInterval.Second, LastRun, Now) > 1 Then
LastRun = Now
' do something
Else
' only once please!
Endif

KeirGordon

It is a very easy solution. The reason you are getting multiple events is because the filesystem watcher watches last access time, and everytime you touch the file it is cuasing another event to be thrown... simply put an if statement around your code to restrict event types. You only want your code to run if e.ChangeType = IO.WatcherChangeTypes.Created .... but the way you have it written it will run no matter what change occurs. Do it like I have below:

Private Sub FileSystemWatcher1_Changed(ByVal sender As System.Object, ByVal e As System.IO.FileSystemEventArgs) Handles FileSystemWatcher1.Changed

if e.ChangeType = IO.WatcherChangeTypes.Created then

Dim imgFile As System.Drawing.Image = System.Drawing.Image.FromFile("C:\FolderA\image.bmp")
imgFile.Save("C:\FolderB\image.gif", System.Drawing.Imaging.ImageFormat.Gif)

Process.Start("Folder B") 'to open folder where there is the gif image

SendKeys.SendWait(" ")
SendKeys.SendWait("%fn")
SendKeys.SendWait("{RIGHT}")
SendKeys.SendWait("{ENTER}")
SendKeys.SendWait("%fc")

end if
end sub

chspit

ASKER

Hi KeirGordon,
if i try as you said, nothing happens...the event is not raised.
When in the beginning I create the FileSystemWatcher I specify the NotifyFilter to LastAccess. so if I then add your line, still nothing happens when a new file is created.

ASKER CERTIFIED SOLUTION

tgannetts

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