CreateFile (was: Convert to VB.NET)

[Andrew Clark]

Hello,

Thanks for all replies on this subject. I still cannot get CreateFile to
retun a good value though. I went to PInvoke.net and saw the VB.NET
declaration of this function:

<DllImport("ker nel32.dll", SetLastError:=T rue)> Private Shared Function
CreateFile(ByVa l lpFileName As String, ByVal dwDesiredAccess As
EFileAccess, ByVal dwShareMode As EFileShare, ByVal lpSecurityAttri butes
As IntPtr, ByVal dwCreationDispo sition As ECreationDispos ition, ByVal
dwFlagsAndAttri butes As EFileAttributes , ByVal hTemplateFile As IntPtr)
As IntPtr
End Function

VB.NET did not like the 'Private Shared' part, so I changed that to
'Public', and all the EFile* types I changed to Integer, so this is what
I end up with:

<DllImport("ker nel32.dll", SetLastError:=T rue)> Public Function
CreateFile(ByVa l lpFileName As String, ByVal dwDesiredAccess As Integer,
ByVal dwShareMode As Integer, ByRef lpSecurityAttri butes As IntPtr, ByVal
dwCreationDispo sition As Integer, ByVal dwFlagsAndAttri butes As Integer,
ByVal hTemplateFile As IntPtr) As IntPtr
End Function

Now VB.NET does not complain at least. I put a break on this statement:

hFile = CreateFile(File Name, GENERIC_READ, 0, IntPtr.Zero, OPEN_EXISTING,
FILE_ATTRIBUTE_ NORMAL, IntPtr.Zero)

and the values are as following:

GENERIC_READ -2147483648
IntPtr.Zero 0
OPEN_EXISTING 3
FILE_ATTRIBUTE_ NORMAL 128

but still I get -1 returned! Thoughts?

Thanks,
Andrew

[rmacias]

Why not use the .NET Framework instead of kernel32?

You can do something like this to open up a file:

Dim fs As FileStream = New FileStream("C:\ filename.txt", FileMode.Open)
Dim arrayOfBytes(10 0) As Byte

Do While fs.Read(arrayOf Bytes, 0, arrayOfBytes.Le ngth) > 0
'Process your file
Loop

Or something like this:
Dim sw As StreamReader = File.OpenText(" C:\filename.txt ")
Dim fileContents As String = sw.ReadToEnd()

Take a look at the System.IO namespace for different classes for File IO.

"Andrew Clark" wrote:

Hello,

Thanks for all replies on this subject. I still cannot get CreateFile to
retun a good value though. I went to PInvoke.net and saw the VB.NET
declaration of this function:

<DllImport("ker nel32.dll", SetLastError:=T rue)> Private Shared Function
CreateFile(ByVa l lpFileName As String, ByVal dwDesiredAccess As
EFileAccess, ByVal dwShareMode As EFileShare, ByVal lpSecurityAttri butes
As IntPtr, ByVal dwCreationDispo sition As ECreationDispos ition, ByVal
dwFlagsAndAttri butes As EFileAttributes , ByVal hTemplateFile As IntPtr)
As IntPtr
End Function

VB.NET did not like the 'Private Shared' part, so I changed that to
'Public', and all the EFile* types I changed to Integer, so this is what
I end up with:

<DllImport("ker nel32.dll", SetLastError:=T rue)> Public Function
CreateFile(ByVa l lpFileName As String, ByVal dwDesiredAccess As Integer,
ByVal dwShareMode As Integer, ByRef lpSecurityAttri butes As IntPtr, ByVal
dwCreationDispo sition As Integer, ByVal dwFlagsAndAttri butes As Integer,
ByVal hTemplateFile As IntPtr) As IntPtr
End Function

Now VB.NET does not complain at least. I put a break on this statement:

hFile = CreateFile(File Name, GENERIC_READ, 0, IntPtr.Zero, OPEN_EXISTING,
FILE_ATTRIBUTE_ NORMAL, IntPtr.Zero)

and the values are as following:

GENERIC_READ -2147483648
IntPtr.Zero 0
OPEN_EXISTING 3
FILE_ATTRIBUTE_ NORMAL 128

but still I get -1 returned! Thoughts?

Thanks,
Andrew

[rmacias]

In addition, if it's a file handle that you seek, you can also do something
like this:

Dim fs As FileStream = New FileStream("C:\ filename.txt", FileMode.Open)
Dim filePtr As IntPtr = fs.Handle
hFile = filePtr.ToInt32 ()

Hope this helps. I haven't tested this, but it's off the top of my head.
Let me know if it works for you.

"rmacias" wrote:

Why not use the .NET Framework instead of kernel32?

You can do something like this to open up a file:

Dim fs As FileStream = New FileStream("C:\ filename.txt", FileMode.Open)
Dim arrayOfBytes(10 0) As Byte

Do While fs.Read(arrayOf Bytes, 0, arrayOfBytes.Le ngth) > 0
'Process your file
Loop

Or something like this:
Dim sw As StreamReader = File.OpenText(" C:\filename.txt ")
Dim fileContents As String = sw.ReadToEnd()

Take a look at the System.IO namespace for different classes for File IO.

"Andrew Clark" wrote:

Hello,

Thanks for all replies on this subject. I still cannot get CreateFile to
retun a good value though. I went to PInvoke.net and saw the VB.NET
declaration of this function:

<DllImport("ker nel32.dll", SetLastError:=T rue)> Private Shared Function
CreateFile(ByVa l lpFileName As String, ByVal dwDesiredAccess As
EFileAccess, ByVal dwShareMode As EFileShare, ByVal lpSecurityAttri butes
As IntPtr, ByVal dwCreationDispo sition As ECreationDispos ition, ByVal
dwFlagsAndAttri butes As EFileAttributes , ByVal hTemplateFile As IntPtr)
As IntPtr
End Function

VB.NET did not like the 'Private Shared' part, so I changed that to
'Public', and all the EFile* types I changed to Integer, so this is what
I end up with:

<DllImport("ker nel32.dll", SetLastError:=T rue)> Public Function
CreateFile(ByVa l lpFileName As String, ByVal dwDesiredAccess As Integer,
ByVal dwShareMode As Integer, ByRef lpSecurityAttri butes As IntPtr, ByVal
dwCreationDispo sition As Integer, ByVal dwFlagsAndAttri butes As Integer,
ByVal hTemplateFile As IntPtr) As IntPtr
End Function

Now VB.NET does not complain at least. I put a break on this statement:

hFile = CreateFile(File Name, GENERIC_READ, 0, IntPtr.Zero, OPEN_EXISTING,
FILE_ATTRIBUTE_ NORMAL, IntPtr.Zero)

and the values are as following:

GENERIC_READ -2147483648
IntPtr.Zero 0
OPEN_EXISTING 3
FILE_ATTRIBUTE_ NORMAL 128

but still I get -1 returned! Thoughts?

Thanks,
Andrew

[Dragon]

Hello,

1. "ByRef lpSecurityAttri butes As IntPtr" does not make sense. As I've
already mentioned, change it to ByVal (or ByRef ... As
SECURITY_ATTRIB UTES if you want them).
2. Check the value of Marshal.GetLast Win32Error() after the unsuccessful
call to CreateFile and look it up in
http://msdn.microsoft.com/library/en...error_codes.as
p

HTH,
Roman

"Andrew Clark" <la*****@hotmai l.com> ñîîáùèë/ñîîáùèëà â íîâîñòÿõ
ñëåäóþùåå: news:1128603805 .64e390952c6e40 cc742b0ff1f5a1f c78@teranews...

Hello,

Thanks for all replies on this subject. I still cannot get CreateFile to retun a good value though. I went to PInvoke.net and saw the VB.NET
declaration of this function:

<DllImport("ker nel32.dll", SetLastError:=T rue)> Private Shared Function CreateFile(ByVa l lpFileName As String, ByVal dwDesiredAccess As
EFileAccess, ByVal dwShareMode As EFileShare, ByVal lpSecurityAttri butes As IntPtr, ByVal dwCreationDispo sition As ECreationDispos ition, ByVal
dwFlagsAndAttri butes As EFileAttributes , ByVal hTemplateFile As IntPtr) As IntPtr
End Function

VB.NET did not like the 'Private Shared' part, so I changed that to
'Public', and all the EFile* types I changed to Integer, so this is what I end up with:

<DllImport("ker nel32.dll", SetLastError:=T rue)> Public Function
CreateFile(ByVa l lpFileName As String, ByVal dwDesiredAccess As Integer, ByVal dwShareMode As Integer, ByRef lpSecurityAttri butes As IntPtr, ByVal dwCreationDispo sition As Integer, ByVal dwFlagsAndAttri butes As Integer, ByVal hTemplateFile As IntPtr) As IntPtr
End Function

Now VB.NET does not complain at least. I put a break on this statement:
hFile = CreateFile(File Name, GENERIC_READ, 0, IntPtr.Zero, OPEN_EXISTING, FILE_ATTRIBUTE_ NORMAL, IntPtr.Zero)

and the values are as following:

GENERIC_READ -2147483648
IntPtr.Zero 0
OPEN_EXISTING 3
FILE_ATTRIBUTE_ NORMAL 128

but still I get -1 returned! Thoughts?

Thanks,
Andrew

[Andrew Clark]

"=?Utf-8?B?cm1hY2lhcw= =?=" <rm*****@newsgr oup.nospam> wrote in
news:9C******** *************** ***********@mic rosoft.com:

In addition, if it's a file handle that you seek, you can also do
something like this:

Dim fs As FileStream = New FileStream("C:\ filename.txt",
FileMode.Open) Dim filePtr As IntPtr = fs.Handle
hFile = filePtr.ToInt32 ()

Hope this helps. I haven't tested this, but it's off the top of my
head. Let me know if it works for you.

Yes, I use CreateFile because I need a file handle. I will try this,
thanks!

Andrew

[Andrew Clark]

"Dragon" <[e-mail] > wrote in news:#EfqEvqyFH A.460
@TK2MSFTNGP15.p hx.gbl:

Hello,

Thanks, but I've decided to scrap the Win32 API. Now I have another issue
and I think I will start another thread.

Thanks to all!
Andrew