FileSystemWatcher Changed Event [resolved]

[jonwondering]

Hey guys, this is probably a simple question, but I am new to VB .net....

I have a FileSystemWatcher object in a Module and it is declared in that Module as public. The variable name is FileWatch. I also have a FileWatch.Changed() event in the same module, but it gives me an error whenever I try to compile:

error BC30506: Handles clause requires a WithEvents variable.

That error points to:

Public Sub FileWatch_Changed(ByVal sender As System.Object, ByVal e As System.IO.FileSystemEventArgs) Handles FileWatch.Changed

I know it's because it is in a module, and not in a form's code, but what do I add with WithEvents?

Thanks,
jonwondering

[JoshuaColeman]

I don't know the answer.

However, the error sorta tells you the error.

If I were to guess, when you declare it, put withevents someone in the declaration.

I don't even know what that means, but I have seen and debugged programs where that was used.

- Josh

[Zakary]

To use the FileSystemWatcher tool, you may add it to the form like a timer or ToolTip. Or when you declare the object manually and want to use its event than declare it with the WithEvents keyword.

Dim WithEvents FileWatch As IO.FileSystemWatcher

[jonwondering]

That solved the compiling problem, but when in the same module I do this:

FileWatch.NotifyFilter = FileWatch.LastAccess

then, application crashes at runtime saying Object reference not set to an instance of an object....

[Zakary]

Add the New Keyword in the declaration ...

Dim WithEvents FileWatch As IO.FileSystemWatcher = New IO.FileSystemWatcher

[jonwondering]

Yeah that works. Thank you very much...

But now for some reason the FileWatch.Changed event is not working at all - it is not executed... could it be because it's located in a module?

Thanks

[Zakary]

Have you set the

FileWatch.EnableRaisingEvents = True

It should look like this ....

Private WithEvents FileWatch As IO.FileSystemWatcher
 
Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    FileWatch = New IO.FileSystemWatcher("C:\Toto")
    FileWatch.NotifyFilter = IO.NotifyFilters.FileName
    FileWatch.EnableRaisingEvents = True
 
End Sub

[jonwondering]

Oh yes. I am sorry - the last one was my stupid mistake. I fixed it now. Thanks for your help Zakary!

[Zakary]

Your are welcome