Text File & List Box

Hi all,
I am supposed to create a program that has the lists of computers for each and every room in the building. This is how it goes:

There is a list box with all rooms in it:

When the user chooses one of them, the list of computers is displayed: I want this list to be stored in a text file. So could someone tell me how can I:
~ Create a text file
~ Write to a text file
~ I want each line from the text file to be an item: how do i do that
~ I want to edit the text file

You could just give me a brief code that allows me to do the above. I will be able to refurb it to use for my methods

Thank you for your help in advance,
I appreciate it
Khanjan

Quote:

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Originally Posted by khanjan_a2k

~ Create a text file

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VB Code:

Open "c:\machines.txt" For Append As # 1

Quote:

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Originally Posted by khanjan_a2k

~ Write to a text file

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VB Code:

Print #1, "MachineName"

Quote:

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Originally Posted by khanjan_a2k

~ I want each line from the text file to be an item: how do i do that

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Print #1 will place each item on a separate line

Quote:

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Originally Posted by khanjan_a2k

~ I want to edit the text file

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Open the file and read the whole thing into a multiline textbox. Do you editing, save the contents back.

For samples and tutroials visit our FAQ section (not to mention this forum with tons of samples).

VB Code:

Dim ff As Integer, i As Integer
Dim ln As String
 
    'to save it
 
    ff = FreeFile 'that is your file number
        Open "C:\test.txt" For Output As #ff 'opening the file (even if it does not exist yet) for writing - output
            For i = 0 To List1.ListCount - 1 'write each list item with the loop
                Print #ff, List1.List (i)
            Next i
        Close #ff 'dont forget to close the file
 
    'to read it
 
    ff = FreeFile
    List1.Clear
 
        Open "c:\test.txt" For Input As #ff 'open it for reading - input
            Do Until EOF (ff) 'read until the end of file
                Line Input #ff, ln 'input each line
                    List1.AddItem ln 'add it to the list
            Loop
        Close #ff

Also, you have a million of samples all over the forums on writing/reading text files.

If you want to get a line from a text box and add it to a list(other than the ways listed with the open functions), like from a textbox within your program for example, you can always check for Chr$(13) / Chr$(10) and do a Mid$() to get it. It's the long way around, but useful sometimes. I wouldn't recommend using it for a very large list, though. It will eat up your memory!

I want to take each line from the text file and put it each line as a seperate item in the listbox... I think you understood me wrong there Hack


Khanjan

Quote:

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Originally Posted by khanjan_a2k

I want to take each line from the text file and put it each line as a seperate item in the listbox...

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That's what my code from post #4 does.

Quote:

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Originally Posted by gavio

VB Code:

Dim ff As Integer, i As Integer
Dim ln As String
 
    'to save it
 
    ff = FreeFile 'that is your file number
        Open "C:\test.txt" For Output As #ff 'opening the file (even if it does not exist yet) for writing - output
            For i = 0 To List1.ListCount - 1 'write each list item with the loop
                Print #ff, List1.List (i)
            Next i
        Close #ff 'dont forget to close the file
 
    'to read it
 
    ff = FreeFile
    List1.Clear
 
        Open "c:\test.txt" For Input As #ff 'open it for reading - input
            Do Until EOF (ff) 'read until the end of file
                Line Input #ff, ln 'input each line
                    List1.AddItem ln 'add it to the list
            Loop
        Close #ff

Also, you have a million of samples all over the forums on writing/reading text files.

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I just tested this, and came up with a problem: it only lists 3000 or so lines in the listbox. I am interested in this code because it seems to be a quick way to add a lot of lines from a text file to a listbox(where as I have been using another method to pull the lines straight from a text box, which results in the app freezing if there are more than a couple thousand lines).

Any way to increase this to add roughly 15,000 lines(ie. thewhole text file?)

Quote:

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Originally Posted by gavio

That's what my code from post #4 does.

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You seem to be fairly knowledgable... think you could help me out with my thread in the API forum by any chance?

Quote:

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Originally Posted by BrendanDavis

I just tested this, and came up with a problem: it only lists 3000 or so lines in the listbox. I am interested in this code because it seems to be a quick way to add a lot of lines from a text file to a listbox(where as I have been using another method to pull the lines straight from a text box, which results in the app freezing if there are more than a couple thousand lines).

Any way to increase this to add roughly 15,000 lines(ie. thewhole text file?)

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This probably is not a number of lines issue as much as it is a memory issue. The listbox control is limited to 32K - you may be exceeding the limit.

Quote:

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Originally Posted by BrendanDavis

Any way to increase this to add roughly 15,000 lines(ie. thewhole text file?)

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Try with a ListView.

Quote:

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Originally Posted by Hack

This probably is not a number of lines issue as much as it is a memory issue. The listbox control is limited to 32K - you may be exceeding the limit.

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That makes sense. I knew it wasn't a line issue, because the last line it added wasn't even a full line.. it was a partial. And also, loading the huge text file in a textbox worked fine, so I figured it was the listbox, not the code.

Quote:

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Originally Posted by gavio

VB Code:

Open "C:\test.txt" For Output As #ff 'opening the file (even if it does not exist yet) for writing - output

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Append will do the same thing, without destroying the file if it does exist. Depends on whether he wants to add everything at once, or be able to add things later.

Well... what I want is to create a text file. Then add the list of computers in the particular room of the bulding. So the user can add the list of computers at the beginning. But I also want to be able to remove or add more computers to the list. So I will be adding a whole lot on the first time. But... in the near future... I will be replacing computers on the text files.

Also I will be storing the history of changes made to each computer... and the history of problems with each computer.

So I guess I will use Append since it will not destroy the file.

Also... lets say I want to remove an item from the middle of the list... How would I do that?

Khanjan

if you need to use the text file to store values quite often, why dont you consider database for this...

Quote:

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Originally Posted by khanjan_a2k

Also... lets say I want to remove an item from the middle of the list... How would I do that?

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Try the following:

VB Code:

Private Sub List1_KeyDown(KeyCode As Integer, Shift As Integer)
    If KeyCode = vbKeyDelete And List1.ListIndex <> -1 Then
        If MsgBox("Are you sure you want to delete " & Chr(34) & List1.List(List1.ListIndex) & Chr(34) & " from the list?", vbQuestion + vbYesNo) = vbYes Then
            List1.RemoveItem (List1.ListIndex)
        End If
    End If
End Sub