Speedy_SgZ

Hi all!

I don't know much about reading and writing files in Visual Basic, that's why I post this question. In the picture I provide with this post you can see 3 blocks of data. Each blocks contains 9 rows (= records in the database)

http://soccer.gamez.nl/temp/vb/1.jpg
Three blocks of data

http://soccer.gamez.nl/temp/vb/2.jpg
One data block

http://soccer.gamez.nl/temp/vb/3.jpg
One row (= 1 record)

http://soccer.gamez.nl/temp/vb/4.jpg
Columns explained

In total the "database" contains 34 blocks of data each containig 9 rows. I'd like to open this database format in Visual Basic. I was thinking about 9 rows with each 5 dropdown boxes. In the first box comes A, in the second box comes B, in the third box comes C, in the fourth box comes D and in the fifth box comes E. I also want to convert the bits and bytes into ASCII.

A: varies from 00 (decimal: 0) to 11 (decimal: 17)
B: varies from 00 (decimal: 0) to 11 (decimal: 17)

C: indicates the day ; varies from 01 (decimal: 1) to 1F (decimal: 31)
D: indicates the month ; varies from 00 (decimal: 0) to 0B (decimal: 11)
E: indicates the year ; varies from 00 (decimal 0) to 01 (decimal 1)

Notes (decimal values used):
The year: 00 = 2003 and 01 = 2004
The month: 00 = January, 11 = December
The day: 01 = day 1, 31 = day 31

Is it possible to create something so when you pick "Block A" in a dropdown menu the 9 records of "Block A" are shown in the dropdowns? And when you choose for instance for "Block Z" it loads the records of "Block Z"? Is there also a way to change the values in the file. If the dropdown box for "day" contains 12 and you change it to 23 it also changes in the file.

I hope I'm clear enough to get some help . Thanks in advance!

Greetings, Speedy

passel

There's a number of ways you could go about this. You should read the
File I/O tutorial in the tutorial section. I'll just give you one way of
getting the information from the file. You can decide what you want to
do with it after that point. You can write the information back to the
file by just changing the "get" to a "put", the rest of the I/O code is
unchanged.

This example defines a record (UDT) in the format you specified. It
creates an array to read all 34 blocks, of 9 records. Once you read the
tutorial you may see how to change the code to read one record, or
one block at a time, if you want.

Speedy_SgZ

Quote:

---

Originally Posted by passel
There's a number of ways you could go about this. You should read the
File I/O tutorial in the tutorial section. I'll just give you one way of
getting the information from the file. You can decide what you want to
do with it after that point. You can write the information back to the
file by just changing the "get" to a "put", the rest of the I/O code is
unchanged.

This example defines a record (UDT) in the format you specified. It
creates an array to read all 34 blocks, of 9 records. Once you read the
tutorial you may see how to change the code to read one record, or
one block at a time, if you want.

Code:

Private Type DateRecType
  bytA As Byte
  bytB As Byte
  int2 As Integer 'don't care
  byt4 As Byte    'don't care
  bytDate As Byte
  bytMonth As Byte
  bytYear As Byte
End Type

Private Sub Command1_Click()
  Dim block(1 To 34, 1 To 9) As DateRecType  '34 blocks of 9 records
  Open "c:\tst.fil" For Binary As #1
    Get #1, , block   'read all 34 blocks
  Close #1
  With block(34, 9)  'Print the information from the 9th record of the 34th block.
    Debug.Print .bytA; .bytB; .bytDate; .bytMonth; .bytYear
  End With
End Sub

---

OK, many many thanks! Works perfect! But now have an other little problem. As you can see on this screenshot I have loaded the first block out of the database. Now I'd like to change the values from 0 till 17 in blocks A en B in text. I know how I can do it in VB, but I'd like to do it with an external file. Any suggestions?

And something else: when changing the date for instance, how can I save the changes to the original file?

http://soccer.gamez.nl/temp/vb/5.jpg

Thanks in advance!

passel

I don't understand your question about using an external file for changing
the values in the A and B values.

To save the changes, assuming you've read all the data in so it's sitting
in the (34,9) array, you just change the "Get" to a "Put" to write all the
data back to the file. Just update the values in the array.

Of course, if you didn't want to write or read the whole file, you can
calculate the position, and only read or write as much as you want.
Each record is 8 bytes, so the byte position would be.
8 * rows * block
1 + ((block-1) * 72) + ((Row-1) * 8)

For the 1,7 example above, the byte position would be
1 + (1-1) * 72) + ((7-1) * 8)
1 + (0 ) + (48 )
49


Since you display a "block", perhaps you just want to read a block, and
write a block.

Plenty of options. It's up to you what you want to do.