vb6 - How to read a file and write into a text file?

Question

I want to open mis file, copy all the data and write into a text file.

My mis file.

File name – 1.mis

M3;3395;44;0;1;;20090404;094144;8193;3;0;;;;
M3;3397;155;0;2;;20090404;105941;8193;3;0;;;;
M3;3396;160;0;1;;20090404;100825;8193;3;0;;;;
M3;3398;168;0;2;;20090404;110106;8193;3;0;;;;

so on...,

The above data should appear in a text file with same file name (1.txt).

I tried this code.

Dim sFileText As String
Dim iFileNo As Integer
iFileNo = FreeFile
Open "C:ClientsConverterClockings.mis" For Input As #iFileNo
Do While Not EOF(iFileNo)
Input #iFileNo, sFileText
Loop
Close #iFileNo

Open "C:ClientsConverter2.txt" For Output As #iFileNo
Do While Not EOF(iFileNo)
Write #iFileNo, sFileText
Loop
Close #iFileNo

Nothing is saved in 1.txt.

Answer 1

It far easier to use the scripting runtime which is installed by default on Windows

Just go project Reference and check Microsoft Scripting Runtime and click OK.

Then you can use this code which is way better than the default file commands

Dim FSO As FileSystemObject
Dim TS As TextStream
Dim TempS As String
Dim Final As String
Set FSO = New FileSystemObject
Set TS = FSO.OpenTextFile("C:ClientsConverterClockings.mis", ForReading)
'Use this for reading everything in one shot
Final = TS.ReadAll
'OR use this if you need to process each line
Do Until TS.AtEndOfStream
    TempS = TS.ReadLine
    Final = Final & TempS & vbCrLf
Loop
TS.Close

Set TS = FSO.OpenTextFile("C:ClientsConverter2.txt", ForWriting, True)
    TS.Write Final
TS.Close
Set TS = Nothing
Set FSO = Nothing

As for what is wrong with your original code here you are reading each line of the text file.

Input #iFileNo, sFileText

Then here you write it out

Write #iFileNo, sFileText

sFileText is a string variable so what is happening is that each time you read, you just replace the content of sFileText with the content of the line you just read.

So when you go to write it out, all you are writing is the last line you read, which is probably a blank line.

Dim sFileText As String
Dim sFinal as String
Dim iFileNo As Integer
iFileNo = FreeFile
Open "C:ClientsConverterClockings.mis" For Input As #iFileNo
Do While Not EOF(iFileNo)
  Input #iFileNo, sFileText
sFinal = sFinal & sFileText & vbCRLF
Loop
Close #iFileNo

iFileNo = FreeFile 'Don't assume the last file number is free to use
Open "C:ClientsConverter2.txt" For Output As #iFileNo
Write #iFileNo, sFinal
Close #iFileNo

Note you don't need to do a loop to write. sFinal contains the complete text of the File ready to be written at one shot. Note that input reads a LINE at a time so each line appended to sFinal needs to have a CR and LF appended at the end to be written out correctly on a MS Windows system. Other operating system may just need a LF (Chr$(10)).

If you need to process the incoming data then you need to do something like this.

Dim sFileText As String
Dim sFinal as String
Dim vTemp as Variant
Dim iFileNo As Integer
Dim C as Collection
Dim R as Collection
Dim I as Long
Set C = New Collection
Set R = New Collection

iFileNo = FreeFile
Open "C:ClientsConverterClockings.mis" For Input As #iFileNo
Do While Not EOF(iFileNo)
  Input #iFileNo, sFileText
  C.Add sFileText
Loop
Close #iFileNo

For Each vTemp in C
     Process vTemp
Next sTemp

iFileNo = FreeFile
Open "C:ClientsConverter2.txt" For Output As #iFileNo
For Each vTemp in R
   Write #iFileNo, vTemp & vbCRLF
Next sTemp
Close #iFileNo