Read Next Line for Check only

[mohan.r1980]

Hello Friends,

I am reading text file and i just want to check what next line contain
but cursor location should not change

e.g.
currently i am reading Line No. 5 (Using ReadLine Function)
now i want to check what Line No. 6 contain
after checking i want to read Line No. 6 (but my cursor location goes on 7th Line)

In Short is it possible to move the current cursor (ReadLine) to Previous line
In short i want to read a single Line twice (Move cursor Backward and forward)

Here is my Code

Dim ReadLine
Dim FN As Integer
Dim FileLoc As String
FileLoc = "D:\Transfer\Sample.txt"
FN = FreeFile
Open FileLoc For Input As #FN    ' Open file.
Do While Not EOF(FN)    ' Loop until end of file.
     
    Line Input #1, ReadLine    ' Get one Line.
    Debug.Print ReadLine     ' Print to the Immediate window.

Loop
Close #FN    ' Close file.

[AlphaFrog]

In Short is it possible to move the current cursor (ReadLine) to Previous line
In short i want to read a single Line twice (Move cursor Backward and forward)

You cannot move the line pointer backwards in Open file For Input mode. It reads sequentially and forward.

You could read each line and keep track of the previous line with another variable. Something like this...

Sub foo()
Dim ReadLine1 As String, ReadLine2 As String
Dim FN As Integer
Dim FileLoc As String
FileLoc = "D:\Transfer\Sample.txt"
FN = FreeFile
Open FileLoc For Input As #FN    ' Open file.
Do While Not EOF(FN)    ' Loop until end of file.
     
    ReadLine1 = ReadLine2
    Line Input #1, ReadLine2    ' Get one Line.
    Debug.Print ReadLine1     ' Print previous line to the Immediate window.
    Debug.Print ReadLine2     ' Print to the Immediate window.

Loop
Close #FN    ' Close file.
End Sub

Alternatively, you could Read the first line, Store the pointer position, Read the next line, close and reopen the same file. Then read up to the stored pointer position.

Also, there are the two other modes; Open for Random Access and Binary. Both have advantages and disadvantages and are a little more complicated. Do a web search for something like VB File Access "Random Access" Binary mode for several useful step-by-step guides. This one looks helpful.
FILE HANDLING USING VISUAL BASIC 6.0 PART I

[mohan.r1980]

hi AlphFrog,

i already tried this solution

[Grul]

Hi Mohan.

You could try reading the lines of the file into an array first.
Then you could access any line at any time.

Dim ReadLine
Dim FN, LineCount As Integer
Dim FileLoc As String
Dim FileArray()
FileLoc = "D:\Transfer\Sample.txt"
FN = FreeFile
LineCount = 0

'First read the lines in the file into an array
Open FileLoc For Input As #FN               'Open file.
    Line Input #1, ReadLine                 'Get one Line.
    LineCount = LineCount + 1               'Increment a counter
    ReDim Preserve FileArray(LineCount)     're-dimension the array so that it can add the new line
    FileArray(LineCount) = ReadLine         'and add the line to the array
Close #FN

'Now read the array instead of the file and you can move backwards and forwards through the lines
For a = 1 To UBound(FileArray)
    Debug.Print FileArray(a)                ' Print to the Immediate window.
    If a > 1 Then
        Debug.Print FileArray(a - 1)        ' Prints the previous line to the Immediate window.
    End If
    If a < UBound(FileArray) Then
        Debug.Print FileArray(a + 1)        ' Prints the next line to the Immediate window.
    End If
Next