CopyFileEx API - NullReferenceException

I am trying to use the CopyFileEx API in a VB.NET app and I am getting a
"object reference not set to an instance of an object" error every time I
run.

If I comment out the callback function definition (cb = AddressOf
Me.myCopyProgressRoutine) then it copies the file just fine but of course I
don't have any way to update progress.

I have simplified and included my code below for anybody to look at. I am
totally out of ideas on this one.

Imports System.Runtime.InteropServices
Public Class Form1
Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

Public Delegate Function CopyProgressRoutine( _
ByVal TotalFileSize As Long, _
ByVal TotalBytesTransferred As Long, _
ByVal StreamSize As Long, _
ByVal StreamBytesTransferred As Long, _
ByVal dwStreamNumber As Long, _
ByVal dwCallbackReason As Long, _
ByVal hSourceFile As Long, _
ByVal hDestinationFile As Long, _
ByVal lpData As Long _
) As Long

Declare Auto Function CopyFileEx Lib "kernel32.dll" ( _
ByVal lpExistingFileName As String, _
ByVal lpNewFileName As String, _
ByVal lpProgressRoutine As CopyProgressRoutine, _
ByVal lpData As Long, _
ByVal lpBool As Long, _
ByVal dwCopyFlags As Long _
) As Boolean

Public Function myCopyProgressRoutine( _
ByVal TotalFileSize As Long, _
ByVal TotalBytesTransfered As Long, _
ByVal StreamSize As Long, _
ByVal StreamBytesTransferred As Long, _
ByVal dwStreamNumber As Long, _
ByVal dqCallbackReason As Long, _
ByVal hSourceFile As Long, _
ByVal hDestinationFile As Long, _
ByVal lpData As Long _
) As Long

copyForm.ProgressBar.Value = TotalBytesTransfered / TotalFileSize *
100

End Function

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Dim cb As CopyProgressRoutine
cb = AddressOf Me.myCopyProgressRoutine
copyForm.Show()
CopyFileEx("c:\eric.log", "c:\logs\eric1.log", cb, 0, False, 0)
copyForm.Hide()

End Sub
End Class


Any ideas as to why the error is occurring?

Thanks,
Eric

> Any ideas as to why the error is occurring?

Eric: Try changing your Longs to Integers.
--
Phil Weber

Phil,

Unfortunately, I have tried that and still have no luck. I must be
miss-defining something else but I can't find it. The new code looks like
this:

Imports System.Runtime.InteropServices
Public Class Form1
Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "


Public Delegate Function CopyProgressRoutine( _
ByVal TotalFileSize As Integer, _
ByVal TotalBytesTransferred As Integer, _
ByVal StreamSize As Integer, _
ByVal StreamBytesTransferred As Integer, _
ByVal dwStreamNumber As Integer, _
ByVal dwCallbackReason As Integer, _
ByVal hSourceFile As Integer, _
ByVal hDestinationFile As Integer, _
ByVal lpData As Integer _
) As Integer

' Here's where the CopyFileEx method is located, and its signature.
Declare Auto Function CopyFileEx Lib "kernel32.dll" ( _
ByVal lpExistingFileName As String, _
ByVal lpNewFileName As String, _
ByVal lpProgressRoutine As CopyProgressRoutine, _
ByVal lpData As Integer, _
ByVal lpBool As Integer, _
ByVal dwCopyFlags As Integer _
) As Integer

Public Function myCopyProgressRoutine( _
ByVal TotalFileSize As Integer, _
ByVal TotalBytesTransfered As Integer, _
ByVal StreamSize As Integer, _
ByVal StreamBytesTransferred As Integer, _
ByVal dwStreamNumber As Integer, _
ByVal dqCallbackReason As Integer, _
ByVal hSourceFile As Integer, _
ByVal hDestinationFile As Integer, _
ByVal lpData As Integer _
) As Integer

copyForm.ProgressBar.Value = TotalBytesTransfered / TotalFileSize *
100

End Function

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Dim cb As CopyProgressRoutine
cb = AddressOf Me.myCopyProgressRoutine
copyForm.Show()
CopyFileEx("c:\eric.log", "c:\logs\eric1.log", cb, 0, False, 0)
copyForm.Hide()

End Sub
End Class

Any Other thoughts...

Thanks,
Eric

"Phil Weber" <pweber@nospam.fawcette.com> wrote in message
news:3d9c9f9f@10.1.10.29...
> > Any ideas as to why the error is occurring?
>
> Eric: Try changing your Longs to Integers.
> --
> Phil Weber
>
>

> Unfortunately, I have tried that and still have no luck.
> I must be mis-defining something else but I can't find it.

Eric: Well, I was able to get your code to run without error by changing your
False parameter in the call to CopyFileEx to 0:

CopyFileEx("c:\eric.log", "c:\logs\eric1.log", cb, 0, 0, 0)

The file gets copied and the callback routine gets called, but
TotalBytesTransfered is always 0, and I have to kill the app in Task Manager. I
don't know what else to suggest at this point.

Why not use SHFileOperation instead? It can display Windows' built-in progress
dialog.
--
Phil Weber

I would use SHFileOperation but I am actually planning on storing the copy
percentage in a var for use elsewhere. This is problem is driving me nuts
because I know it is probably just a simple incorrect declaration somewhere
but I can't seem to find it.

Using API's in .NET at this point can be very problematic.

I have run into the freezing problem but only when I try and copy files
smaller then 10k. Do you have a file that is larger then 1MB that you could
try with?

Thanks for your help,
Eric

"Phil Weber" <pweber@nospam.fawcette.com> wrote in message
news:3d9cacc5@10.1.10.29...
> > Unfortunately, I have tried that and still have no luck.
> > I must be mis-defining something else but I can't find it.
>
> Eric: Well, I was able to get your code to run without error by changing
your
> False parameter in the call to CopyFileEx to 0:
>
> CopyFileEx("c:\eric.log", "c:\logs\eric1.log", cb, 0, 0, 0)
>
> The file gets copied and the callback routine gets called, but
> TotalBytesTransfered is always 0, and I have to kill the app in Task
Manager. I
> don't know what else to suggest at this point.
>
> Why not use SHFileOperation instead? It can display Windows' built-in
progress
> dialog.
> --
> Phil Weber
>
>

> Do you have a file that is larger then 1MB that
> you could try with?

Eric: The file I tested with is 12.8 MB.
--
Phil Weber

"Eric Immerman" <NewsGroup@theatertec.com> wrote in message
news:3d9cb60e@10.1.10.29...
> I would use SHFileOperation but I am actually planning on storing the copy
> percentage in a var for use elsewhere. This is problem is driving me nuts
> because I know it is probably just a simple incorrect declaration
somewhere
> but I can't seem to find it.
>
> Using API's in .NET at this point can be very problematic.
>
> I have run into the freezing problem but only when I try and copy files
> smaller then 10k. Do you have a file that is larger then 1MB that you
could
> try with?
>
> Thanks for your help,
> Eric

Eric,

See my reply over on the microsoft group... I have an example program I
posted.

Tom Shelton

Thanks so much for your help with this. Late last night a friend of mine
also sent me a solution. He did it with the code changes below. Working
with API's in VB.NET can definitely by problematic. It is basically like
working with a Rubik Cube and trying to find the correct combination that
will allow you to cast the variables. I would pay big money for a good .NET
resource that had all the API functions converted for .NET.

Although I guess most have already been converted to some sort of built in
function in .NET there are still a few that come in very handy.

Public Delegate Function CopyProgressRoutine( _
ByVal TotalFileSize As int64, _
ByVal TotalBytesTransferred As int64, _
ByVal StreamSize As int64, _
ByVal StreamBytesTransferred As int64, _
ByVal dwStreamNumber As Int32, _
ByVal dwCallbackReason As Int32, _
ByVal hSourceFile As Int32, _
ByVal hDestinationFile As Int32, _
ByVal lpData As Int32 _
) As Int32

Declare Auto Function CopyFileEx Lib "kernel32.dll" ( _
ByVal lpExistingFileName As String, _
ByVal lpNewFileName As String, _
ByVal lpProgressRoutine As CopyProgressRoutine, _
ByVal lpData As Int32, _
ByVal lpBool As Int32, _
ByVal dwCopyFlags As Int32 _
) As Int32


Thanks Again,
Eric

"Tom Shelton" <tom@mtogden.com> wrote in message news:3d9ce4e7@10.1.10.29...
>
> "Eric Immerman" <NewsGroup@theatertec.com> wrote in message
> news:3d9cb60e@10.1.10.29...
> > I would use SHFileOperation but I am actually planning on storing the
copy
> > percentage in a var for use elsewhere. This is problem is driving me
nuts
> > because I know it is probably just a simple incorrect declaration
> somewhere
> > but I can't seem to find it.
> >
> > Using API's in .NET at this point can be very problematic.
> >
> > I have run into the freezing problem but only when I try and copy files
> > smaller then 10k. Do you have a file that is larger then 1MB that you
> could
> > try with?
> >
> > Thanks for your help,
> > Eric
>
> Eric,
>
> See my reply over on the microsoft group... I have an example program I
> posted.
>
> Tom Shelton
>
>