API FindFirstFile\F indNextFile vs GetFiles

[Lance]

Hi All,

I'm working on a program that requires searching multiple drives for multiple file types
and cataloging them based on certain geospatial attributes. All together, there are
hundreds of thousands of files on the drives. As part of the process, I'm currently using
the GetFiles method of the FileSystem object to retrieve collection of strings
representing a collection of a particular file type (for example, tif files). The problem
is that the GetFiles method doesn't seem to make any callbacks that would allow for me to
show some sort of meaningful progress, and the process can take a very long time. I know
I could fudge it with a marquee style progress bar and\or a busy mouse icon, but this
isn't ideal.

So, I was looking into using the API to do the grunt work. This would allow me to at
least display each filename in a label control as the search is being performed. I'm
trying to port Randy Birch's VB6 code available on his website at
http://vbnet.mvps.org/code/fileapi/r...l_multiple.htm . It's working
somewhat, except for the FindNextFile function which I've declared like so:

/////
Private Declare Function FindNextFile Lib "kernel32" _
Alias "FindNextFi leA" _
(ByVal hFindFile As Int32, _
ByVal lpFindFileData As WIN32_FIND_DATA ) As IntPtr
/////

As currently implemented, the function is not moving the search to the next file. It is
always returning the first file in the directory and it returns all the properties of that
file correctly. And it returns this first file for as many times as there are files in
the directory. I'm thinking it's because the WIN32_FIND_DATA - which is a UDT in the VB6
code - is defined as an object in my code and Dim'd as

/////
Dim WFD As WIN32_FIND_DATA = New WIN32_FIND_DATA
/////

at the beginning of the SearchForFiles Sub. For reference, in my code WIN32_FIND_DATA
defined like so:

/////
<StructLayout(L ayoutKind.Seque ntial, _
CharSet:=CharSe t.Auto)_
Friend Class WIN32_FIND_DATA
Friend sfileAttributes As Int32 = 0
Friend creationTime_lo wDateTime As Int32 = 0
Friend creationTime_hi ghDateTime As Int32 = 0
Friend lastAccessTime_ lowDateTime As Int32 = 0
Friend lastAccessTime_ highDateTime As Int32 = 0
Friend lastWriteTime_l owDateTime As Int32 = 0
Friend lastWriteTime_h ighDateTime As Int32 = 0
Friend nFileSizeHigh As Int32 = 0
Friend nFileSizeLow As Int32 = 0
Friend dwReserved0 As Int32 = 0
Friend dwReserved1 As Int32 = 0
<MarshalAs(Unma nagedType.ByVal TStr, SizeConst:=MAX_ PATH)_
Friend fileName As String = Nothing
<MarshalAs(Unma nagedType.ByVal TStr, SizeConst:=14)_
Friend alternateFileNa me As String = Nothing
End Class
/////

How can I make it so the FindNextFile call actually moves on to the next file in the
directory?

Lance

[Lance]

what the heck? I didn't define WIN32_FIND_DATA as an object. It's a structure. There
goes my theory. Ugh, not enough coffee this morning. I'd still be interested in your
thoughts as to why the FindNextFile API function isn't working correctly.

Lance

"Lance" <nu***@business .comwrote in message
news:%2******** ********@TK2MSF TNGP03.phx.gbl. ..

Hi All,

I'm working on a program that requires searching multiple drives for multiple file types
and cataloging them based on certain geospatial attributes. All together, there are
hundreds of thousands of files on the drives. As part of the process, I'm currently
using the GetFiles method of the FileSystem object to retrieve collection of strings
representing a collection of a particular file type (for example, tif files). The
problem is that the GetFiles method doesn't seem to make any callbacks that would allow
for me to show some sort of meaningful progress, and the process can take a very long
time. I know I could fudge it with a marquee style progress bar and\or a busy mouse
icon, but this isn't ideal.

So, I was looking into using the API to do the grunt work. This would allow me to at
least display each filename in a label control as the search is being performed. I'm
trying to port Randy Birch's VB6 code available on his website at
http://vbnet.mvps.org/code/fileapi/r...l_multiple.htm . It's working
somewhat, except for the FindNextFile function which I've declared like so:

/////
Private Declare Function FindNextFile Lib "kernel32" _
Alias "FindNextFi leA" _
(ByVal hFindFile As Int32, _
ByVal lpFindFileData As WIN32_FIND_DATA ) As IntPtr
/////

As currently implemented, the function is not moving the search to the next file. It is
always returning the first file in the directory and it returns all the properties of
that file correctly. And it returns this first file for as many times as there are
files in the directory. I'm thinking it's because the WIN32_FIND_DATA - which is a UDT
in the VB6 code - is defined as an object in my code and Dim'd as

/////
Dim WFD As WIN32_FIND_DATA = New WIN32_FIND_DATA
/////

at the beginning of the SearchForFiles Sub. For reference, in my code WIN32_FIND_DATA
defined like so:

/////
<StructLayout(L ayoutKind.Seque ntial, _
CharSet:=CharSe t.Auto)_
Friend Class WIN32_FIND_DATA
Friend sfileAttributes As Int32 = 0
Friend creationTime_lo wDateTime As Int32 = 0
Friend creationTime_hi ghDateTime As Int32 = 0
Friend lastAccessTime_ lowDateTime As Int32 = 0
Friend lastAccessTime_ highDateTime As Int32 = 0
Friend lastWriteTime_l owDateTime As Int32 = 0
Friend lastWriteTime_h ighDateTime As Int32 = 0
Friend nFileSizeHigh As Int32 = 0
Friend nFileSizeLow As Int32 = 0
Friend dwReserved0 As Int32 = 0
Friend dwReserved1 As Int32 = 0
<MarshalAs(Unma nagedType.ByVal TStr, SizeConst:=MAX_ PATH)_
Friend fileName As String = Nothing
<MarshalAs(Unma nagedType.ByVal TStr, SizeConst:=14)_
Friend alternateFileNa me As String = Nothing
End Class
/////

How can I make it so the FindNextFile call actually moves on to the next file in the
directory?

Lance

[Mike McIntyre]

You could call the GetFiles method via a BackgroundWorke r. In your get
files method you could call the BackgroundWorke r ReportProgress method each
time a file is found/processed and in a handler for the BackgoundWorker
ProgressChanged event this will raise you could update the label control
with the filename.

For a free Visual Studio 2005 solution that provides source code for using
the BackgroundWorke r class visit ->
http://www.getdotnetcode.com/GdncSto...orkerClass.htm

--
Mike

Mike McIntyre [MVP]
http://www.getdotnetcode.com
"Lance" <nu***@business .comwrote in message
news:%2******** ********@TK2MSF TNGP03.phx.gbl. ..

Hi All,

I'm working on a program that requires searching multiple drives for
multiple file types and cataloging them based on certain geospatial
attributes. All together, there are hundreds of thousands of files on the
drives. As part of the process, I'm currently using the GetFiles method
of the FileSystem object to retrieve collection of strings representing a
collection of a particular file type (for example, tif files). The
problem is that the GetFiles method doesn't seem to make any callbacks
that would allow for me to show some sort of meaningful progress, and the
process can take a very long time. I know I could fudge it with a marquee
style progress bar and\or a busy mouse icon, but this isn't ideal.

So, I was looking into using the API to do the grunt work. This would
allow me to at least display each filename in a label control as the
search is being performed. I'm trying to port Randy Birch's VB6 code
available on his website at
http://vbnet.mvps.org/code/fileapi/r...l_multiple.htm .
It's working somewhat, except for the FindNextFile function which I've
declared like so:

/////
Private Declare Function FindNextFile Lib "kernel32" _
Alias "FindNextFi leA" _
(ByVal hFindFile As Int32, _
ByVal lpFindFileData As WIN32_FIND_DATA ) As IntPtr
/////

As currently implemented, the function is not moving the search to the
next file. It is always returning the first file in the directory and it
returns all the properties of that file correctly. And it returns this
first file for as many times as there are files in the directory. I'm
thinking it's because the WIN32_FIND_DATA - which is a UDT in the VB6
code - is defined as an object in my code and Dim'd as

/////
Dim WFD As WIN32_FIND_DATA = New WIN32_FIND_DATA
/////

at the beginning of the SearchForFiles Sub. For reference, in my code
WIN32_FIND_DATA defined like so:

/////
<StructLayout(L ayoutKind.Seque ntial, _
CharSet:=CharSe t.Auto)_
Friend Class WIN32_FIND_DATA
Friend sfileAttributes As Int32 = 0
Friend creationTime_lo wDateTime As Int32 = 0
Friend creationTime_hi ghDateTime As Int32 = 0
Friend lastAccessTime_ lowDateTime As Int32 = 0
Friend lastAccessTime_ highDateTime As Int32 = 0
Friend lastWriteTime_l owDateTime As Int32 = 0
Friend lastWriteTime_h ighDateTime As Int32 = 0
Friend nFileSizeHigh As Int32 = 0
Friend nFileSizeLow As Int32 = 0
Friend dwReserved0 As Int32 = 0
Friend dwReserved1 As Int32 = 0
<MarshalAs(Unma nagedType.ByVal TStr, SizeConst:=MAX_ PATH)_
Friend fileName As String = Nothing
<MarshalAs(Unma nagedType.ByVal TStr, SizeConst:=14)_
Friend alternateFileNa me As String = Nothing
End Class
/////

How can I make it so the FindNextFile call actually moves on to the next
file in the directory?

Lance

[Lance]

I thought about that but assumed the GetFiles method would still not report any progress
back to the BackgroundWorke r. Admittedly, I'm a little hazy on how the BackgroundWorke r
receives messages anyway. It was my understanding that if the GetFiles method didn't make
callbacks, then well, it didn't make callbacks.

Another thing that is attractive about the API method, though, is that I can search for
multiple file types at once. GetFiles seems to be limited to one type at a time. I would
be searching for and cataloging about a dozen different file types

Lance

"Mike McIntyre" <mi****@getdotn etcode.comwrote in message
news:eE******** *****@TK2MSFTNG P05.phx.gbl...

You could call the GetFiles method via a BackgroundWorke r. In your get files method you
could call the BackgroundWorke r ReportProgress method each time a file is
found/processed and in a handler for the BackgoundWorker ProgressChanged event this will
raise you could update the label control with the filename.

For a free Visual Studio 2005 solution that provides source code for using the
BackgroundWorke r class visit ->
http://www.getdotnetcode.com/GdncSto...orkerClass.htm

--
Mike

Mike McIntyre [MVP]
http://www.getdotnetcode.com
"Lance" <nu***@business .comwrote in message
news:%2******** ********@TK2MSF TNGP03.phx.gbl. ..

>Hi All,

I'm working on a program that requires searching multiple drives for multiple file
types and cataloging them based on certain geospatial attributes. All together, there
are hundreds of thousands of files on the drives. As part of the process, I'm
currently using the GetFiles method of the FileSystem object to retrieve collection of
strings representing a collection of a particular file type (for example, tif files).
The problem is that the GetFiles method doesn't seem to make any callbacks that would
allow for me to show some sort of meaningful progress, and the process can take a very
long time. I know I could fudge it with a marquee style progress bar and\or a busy
mouse icon, but this isn't ideal.

So, I was looking into using the API to do the grunt work. This would allow me to at
least display each filename in a label control as the search is being performed. I'm
trying to port Randy Birch's VB6 code available on his website at
http://vbnet.mvps.org/code/fileapi/r...l_multiple.htm . It's working
somewhat, except for the FindNextFile function which I've declared like so:

/////
Private Declare Function FindNextFile Lib "kernel32" _
Alias "FindNextFi leA" _
(ByVal hFindFile As Int32, _
ByVal lpFindFileData As WIN32_FIND_DATA ) As IntPtr
/////

As currently implemented, the function is not moving the search to the next file. It
is always returning the first file in the directory and it returns all the properties
of that file correctly. And it returns this first file for as many times as there are
files in the directory. I'm thinking it's because the WIN32_FIND_DATA - which is a
UDT in the VB6 code - is defined as an object in my code and Dim'd as

/////
Dim WFD As WIN32_FIND_DATA = New WIN32_FIND_DATA
/////

at the beginning of the SearchForFiles Sub. For reference, in my code WIN32_FIND_DATA
defined like so:

/////
<StructLayout( LayoutKind.Sequ ential, _
CharSet:=CharS et.Auto)_
Friend Class WIN32_FIND_DATA
Friend sfileAttributes As Int32 = 0
Friend creationTime_lo wDateTime As Int32 = 0
Friend creationTime_hi ghDateTime As Int32 = 0
Friend lastAccessTime_ lowDateTime As Int32 = 0
Friend lastAccessTime_ highDateTime As Int32 = 0
Friend lastWriteTime_l owDateTime As Int32 = 0
Friend lastWriteTime_h ighDateTime As Int32 = 0
Friend nFileSizeHigh As Int32 = 0
Friend nFileSizeLow As Int32 = 0
Friend dwReserved0 As Int32 = 0
Friend dwReserved1 As Int32 = 0
<MarshalAs(Unm anagedType.ByVa lTStr, SizeConst:=MAX_ PATH)_
Friend fileName As String = Nothing
<MarshalAs(Unm anagedType.ByVa lTStr, SizeConst:=14)_
Friend alternateFileNa me As String = Nothing
End Class
/////

How can I make it so the FindNextFile call actually moves on to the next file in the
directory?

Lance

[Tom Shelton]

Lance wrote:

Hi All,

I'm working on a program that requires searching multiple drives for multiple file types
and cataloging them based on certain geospatial attributes. All together, there are
hundreds of thousands of files on the drives. As part of the process, I'm currently using
the GetFiles method of the FileSystem object to retrieve collection of strings
representing a collection of a particular file type (for example, tif files). The problem
is that the GetFiles method doesn't seem to make any callbacks that would allow for me to
show some sort of meaningful progress, and the process can take a very long time. I know
I could fudge it with a marquee style progress bar and\or a busy mouse icon, but this
isn't ideal.

So, I was looking into using the API to do the grunt work. This would allow me to at
least display each filename in a label control as the search is being performed. I'm
trying to port Randy Birch's VB6 code available on his website at
http://vbnet.mvps.org/code/fileapi/r...l_multiple.htm . It's working
somewhat, except for the FindNextFile function which I've declared like so:

/////
Private Declare Function FindNextFile Lib "kernel32" _
Alias "FindNextFi leA" _
(ByVal hFindFile As Int32, _
ByVal lpFindFileData As WIN32_FIND_DATA ) As IntPtr
/////

The default in VB.NET functions is ByVal now rather then ByRef. If you
look at the original, your structure should be passed ByRef. Also, I
would not alias this function - it will cause you serious performance
issues on NT based systems (most current OS's :)

Your declares should probably look more like:

Private Declare Auto Function FindFirstFile Lib "kernel32" _
(ByVal lpFileName As String, _
ByRef lpFindData As WIN32_FIND_DATA ) As IntPtr

Private Declare Auto Function FindNextFile Lib "kernel32" _
(ByVal hFindFile As IntPtr, _
ByRef lpFindData As WIN32_FIND_DATA ) As IntPtr

Private Delcare Function FindClose Lib "kernel32" _
(ByVal hFindFile As IntPtr) As Boolean

--
Tom Shelton

[Tom Shelton]

Tom Shelton wrote:

Lance wrote:

Hi All,

I'm working on a program that requires searching multiple drives for multiple file types
and cataloging them based on certain geospatial attributes. All together, there are
hundreds of thousands of files on the drives. As part of the process, I'm currently using
the GetFiles method of the FileSystem object to retrieve collection of strings
representing a collection of a particular file type (for example, tif files). The problem
is that the GetFiles method doesn't seem to make any callbacks that would allow for me to
show some sort of meaningful progress, and the process can take a very long time. I know
I could fudge it with a marquee style progress bar and\or a busy mouse icon, but this
isn't ideal.

So, I was looking into using the API to do the grunt work. This would allow me to at
least display each filename in a label control as the search is being performed. I'm
trying to port Randy Birch's VB6 code available on his website at
http://vbnet.mvps.org/code/fileapi/r...l_multiple.htm . It's working
somewhat, except for the FindNextFile function which I've declared like so:

/////
Private Declare Function FindNextFile Lib "kernel32" _
Alias "FindNextFi leA" _
(ByVal hFindFile As Int32, _
ByVal lpFindFileData As WIN32_FIND_DATA ) As IntPtr
/////

The default in VB.NET functions is ByVal now rather then ByRef. If you
look at the original, your structure should be passed ByRef. Also, I
would not alias this function - it will cause you serious performance
issues on NT based systems (most current OS's :)

Your declares should probably look more like:

Private Declare Auto Function FindFirstFile Lib "kernel32" _
(ByVal lpFileName As String, _
ByRef lpFindData As WIN32_FIND_DATA ) As IntPtr

Private Declare Auto Function FindNextFile Lib "kernel32" _
(ByVal hFindFile As IntPtr, _
ByRef lpFindData As WIN32_FIND_DATA ) As IntPtr

Crap messed up FindNextFile - it should return Boolean rather then
IntPtr.

--
Tom Shelton

[Lance]

Ok. Initially I pasted your API declares in my code and ran it. I was presented with a
"FatalExecution EngineError was detected" message from the MDA. So I changed the
WIN32_FIND_DATA from how it was originally posted as a class (and it *was* a class, not a
structure in my orginal post. I sent a reply to my original message saying it was a
structure <--wrong...ignore my own reply to the original please) to a structure as such:

////
Public Structure WIN32_FIND_DATA
Public sfileAttributes As Int32
Public creationTime_lo wDateTime As Int32
Public creationTime_hi ghDateTime As Int32
Public lastAccessTime_ lowDateTime As Int32
Public lastAccessTime_ highDateTime As Int32
Public lastWriteTime_l owDateTime As Int32
Public lastWriteTime_h ighDateTime As Int32
Public nFileSizeHigh As Int32
Public nFileSizeLow As Int32
Public dwReserved0 As Int32
Public dwReserved1 As Int32
<MarshalAs(Unma nagedType.ByVal TStr, SizeConst:=MAX_ PATH)_
Public fileName As String
<MarshalAs(Unma nagedType.ByVal TStr, SizeConst:=14)_
Public alternateFileNa me As String
End Structure
////

and while now the FindNextFile API call works (yeah!), I don't think the structure is
correct. The filename member is always just the first character of the actual file name
(i.e., ReadMe.Txt is shown as "R") and the lowDates and highDates are too high for a
date-representing value.

Lance
"Tom Shelton" <to*@mtogden.co mwrote in message
news:11******** **************@ m73g2000cwd.goo glegroups.com.. .

>
Tom Shelton wrote:

>Lance wrote:

Hi All,

I'm working on a program that requires searching multiple drives for multiple file
types
and cataloging them based on certain geospatial attributes. All together, there are
hundreds of thousands of files on the drives. As part of the process, I'm currently
using
the GetFiles method of the FileSystem object to retrieve collection of strings
representing a collection of a particular file type (for example, tif files). The
problem
is that the GetFiles method doesn't seem to make any callbacks that would allow for
me to
show some sort of meaningful progress, and the process can take a very long time. I
know
I could fudge it with a marquee style progress bar and\or a busy mouse icon, but this
isn't ideal.

So, I was looking into using the API to do the grunt work. This would allow me to at
least display each filename in a label control as the search is being performed. I'm
trying to port Randy Birch's VB6 code available on his website at
http://vbnet.mvps.org/code/fileapi/r...l_multiple.htm . It's
working
somewhat, except for the FindNextFile function which I've declared like so:

/////
Private Declare Function FindNextFile Lib "kernel32" _
Alias "FindNextFi leA" _
(ByVal hFindFile As Int32, _
ByVal lpFindFileData As WIN32_FIND_DATA ) As IntPtr
/////

The default in VB.NET functions is ByVal now rather then ByRef. If you
look at the original, your structure should be passed ByRef. Also, I
would not alias this function - it will cause you serious performance
issues on NT based systems (most current OS's :)

Your declares should probably look more like:

Private Declare Auto Function FindFirstFile Lib "kernel32" _
(ByVal lpFileName As String, _
ByRef lpFindData As WIN32_FIND_DATA ) As IntPtr

Private Declare Auto Function FindNextFile Lib "kernel32" _
(ByVal hFindFile As IntPtr, _
ByRef lpFindData As WIN32_FIND_DATA ) As IntPtr

Crap messed up FindNextFile - it should return Boolean rather then
IntPtr.

--
Tom Shelton

[Tom Shelton]

Lance wrote:

Ok. Initially I pasted your API declares in my code and ran it. I was presented with a
"FatalExecution EngineError was detected" message from the MDA. So I changed the
WIN32_FIND_DATA from how it was originally posted as a class (and it *was* a class, not a
structure in my orginal post. I sent a reply to my original message saying it was a
structure <--wrong...ignore my own reply to the original please) to a structure as such:

Aaah! I didn't notice that you were using a class instead of a
structure. I will take a stab at doing an actual conversion of the
code this evening (no time right now) - unless someone else beats me to
it :)

--
Tom Shelton

[Lance]

Thanks Tom. Remember, WIN32_FIND_DATA as a class caused the "FatalExecution EngineError "
using your declarations, but as a structure, it was running (although the output of the
members didn't seem to jive).

Lance
"Tom Shelton" <to*@mtogden.co mwrote in message
news:11******** *************@i 3g2000cwc.googl egroups.com...

>
Lance wrote:

>Ok. Initially I pasted your API declares in my code and ran it. I was presented with
a
"FatalExecutio nEngineError was detected" message from the MDA. So I changed the
WIN32_FIND_DAT A from how it was originally posted as a class (and it *was* a class,
not a
structure in my orginal post. I sent a reply to my original message saying it was a
structure <--wrong...ignore my own reply to the original please) to a structure as
such:

Aaah! I didn't notice that you were using a class instead of a
structure. I will take a stab at doing an actual conversion of the
code this evening (no time right now) - unless someone else beats me to
it :)

--
Tom Shelton

[Herfried K. Wagner [MVP]]

"Lance" <nu***@business .comschrieb:

I'm working on a program that requires searching multiple drives for
multiple file types and cataloging them based on certain geospatial
attributes. All together, there are hundreds of thousands of files on the
drives. As part of the process, I'm currently using the GetFiles method
of the FileSystem object to retrieve collection of strings representing a
collection of a particular file type (for example, tif files). The
problem is that the GetFiles method doesn't seem to make any callbacks
that would allow for me to show some sort of meaningful progress, and the
process can take a very long time.

<URL:http://dotnet.mvps.org/dotnet/samples/filesystem/FileSystemEnume rator.zip>

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>