Ad:

Visual Basic 4 / 5 / 6 Discussion Thread
Unsolved
Views: 4941

Aug 1st, 2006

Need help with Binary files and data types in VB6

Expand Post »

Hello all,

I am reading (get) and writing (put) values from multiple binary files.

I first have to copy a binary file file1.bin to file2.bin and then I append 1 record to file2.bin.

My problem is when I read the following code I am not getting the values I expect:

Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text)
Dim iFileNo as Integer
Dim bVer as Byte
Dim lNumberOfFiles as Long
Dim lBufferSize as Long
Dim tBuffer as String
 
FileNum = FreeFile
Open tBinaryFilepath For Binary Access Read Lock Read Write As #FileNum
Get #FileNum, , iFileNo
Get #FileNum, , bVer
Get #FileNum, , lNumberOfFiles
Get #FileNum, , lBufferSize
tBuffer = String(lBufferSize, "")
Get #FileNum, , tBuffer
Dim iFileNo as Integer
Dim bVer as Byte
Dim lNumberOfFiles as Long
Dim lBufferSize as Long
Dim tBuffer as String

FileNum = FreeFile
Open tBinaryFilepath For Binary Access Read Lock Read Write As #FileNum
Get #FileNum, , iFileNo
Get #FileNum, , bVer
Get #FileNum, , lNumberOfFiles
Get #FileNum, , lBufferSize
tBuffer = String(lBufferSize, "")
Get #FileNum, , tBuffer

The only value that is correct is iFileNo. Everything after that is incorrect. For instance bVer should be 1 but comes out as 0. lNumber of Files should be 70 but comes out as 6816000, etc

Any help with this matter is greatly appreciated.

Thank you.

Similar Threads

C++ Data Types in C++

cyman73

Reputation Points: 10

Solved Threads: 0

Newbie Poster

Offline

11 posts
since Jul 2006

Permalink

Aug 1st, 2006

Re: Need help with Binary files and data types in VB6

I noticed there is no loop here, so I'm guessing that was excluded from the excerpt, OR you are only reading that info once..... is it possible for you attach the project along with a sample .bin file that you have so that I can trace through the code?

Comatose

Team Colleague

Reputation Points: 361

Solved Threads: 214

Taboo Programmer

Offline

2,413 posts
since Dec 2004

Permalink

Aug 4th, 2006

Re: Need help with Binary files and data types in VB6

Deleted..
Please see below

Last edited by cyman73; Aug 4th, 2006 at 3:10 pm.

cyman73

Reputation Points: 10

Solved Threads: 0

Newbie Poster

Offline

11 posts
since Jul 2006

Permalink

Aug 4th, 2006

Re: Need help with Binary files and data types in VB6

Hey Comatose,

I do have a loop, but did not include in my example.

I used a hex editor to see exactly what the binary file contained.

Apparently, even if the first value was written as an integer in delphi 4 bytes, I had to use a long in VB6 to capture all 4 bytes. So now I figured out what I need to do to make it work. I am not sure I fully understand it though.

Here is what the first few fields look like according to the hex editor
39 1B 00 00 01 46 ...
__________ __ __

Thank you.

cyman73

Reputation Points: 10

Solved Threads: 0

Newbie Poster

Offline

11 posts
since Jul 2006

Permalink

Aug 4th, 2006

Re: Need help with Binary files and data types in VB6

Follow up issue,
How can I write string contents to a binary file that would not be visible in a Hex editor as text?

Maybe I need to write as binary data? How does one convert a string to hex or binary?

Thanks.

cyman73

Reputation Points: 10

Solved Threads: 0

Newbie Poster

Offline

11 posts
since Jul 2006

Permalink

Aug 4th, 2006

Re: Need help with Binary files and data types in VB6

Follow up to my Binary file problem...

Hello all,
I am trying to write a string preceded by a length field in a binary file
Here is an example

Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text)
Dim tNameBin as String
Dim lBufferSize as Long
:
'Name Field
tNameBin = "UserName" 
lBufferSize = Len(tNameBin) 
Put #TempFileNum, , lBufferSize
Put #TempFileNum, , tNameBin
Dim tNameBin as String
Dim lBufferSize as Long
:
'Name Field
tNameBin = "UserName" 
lBufferSize = Len(tNameBin) 
Put #TempFileNum, , lBufferSize
Put #TempFileNum, , tNameBin

I am using a Hex editor to view the binary file.
After the first Put statement I see the following
08 00 00 00 ....

After the second Put statement I see the following
08 00 00 00 08 00 08 00 55 73 65 72 4E 61 6D ........UserName

My problem is that I see an extra 4 bytes of stuff preceding UserName, above in Bold. I do not want the extra bytes because they are messing up my binary file.

Any ideas are greatly appreciated.
Thank you.

Last edited by cyman73; Aug 4th, 2006 at 9:25 pm.

cyman73

Reputation Points: 10

Solved Threads: 0

Newbie Poster

Offline

11 posts
since Jul 2006

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

Previous Thread in Visual Basic 4 / 5 / 6 Forum Timeline: VB source code for Internet base webcam

Next Thread in Visual Basic 4 / 5 / 6 Forum Timeline: Novice help appreciated please

DaniWeb Message

Cancel Changes

User Name
Password