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'Text File Handling - How to read text file contents for a given file (in four ways)
'Using Non-FSO:

Public Function ReadTextFileContents(filename As String) As String
    Dim fnum As Integer, isOpen As Boolean
    On Error GoTo Error_Handler
    ' Get the next free file number.
    fnum = FreeFile()
    Open filename For Input As #fnum
    ' If execution flow got here, the file has been open without error.
    isOpen = True
    ' Read the entire contents in one single operation.
    ReadTextFileContents = Input(LOF(fnum), fnum)
    ' Intentionally flow into the error handler to close the file.
Error_Handler:
    ' Raise the error (if any), but first close the file.
    If isOpen Then Close #fnum
    If Err Then Err.Raise Err.Number, , Err.Description
End Function
 
' Load a text file into a TextBox control.
Text1.Text = ReadTextFileContents("c:\bootlog.txt")
 
'Using FSO:
'Set a reference to "Microsoft Scripting Runtime"

Public Function ReadTextFileContentUsingFSO(ByVal sFileName As String) As String
    Dim fs As FileSystemObject
    Dim ts As TextStream
    Dim strText As String
    Set fs = New FileSystemObject
    'To Read
    If fs.FileExists(sFileName) Then
        Set ts = fs.OpenTextFile(sFileName)
        Do While Not ts.AtEndOfStream
            strText = strText & ts.ReadLine & vbCrLf
        Loop
        ts.Close
    End If
    ReadTextFileContent = strText
    Set ts = Nothing
    Set fs = Nothing
End Function
 
'Using Binary mode:

Public Function ReadTextFileContentUsingBinaryMode(ByVal sFileName As String) As String
    Dim handle As Integer
    ' ensure that the file exists
    If Len(Dir$(sFileName)) = 0 Then
        Err.Raise 53  ' File not found
    End If
    ' open in binary mode
    handle = FreeFile
    Open sFileName$ For Binary As #handle
    ' read the string and close the file
    ReadTextFileContentUsingBinaryMode = Space$(LOF(handle))
    Get #handle, , ReadTextFileContentUsingBinaryMode
    Close #handle
End Function
 
'Fastest way if you are dealing with large text files

Public Function TextFromFile(ByVal fInStream As String) As String
'Returns text in file fInStream
'Example usage: Debug.Print TextFromFile ("C:\WINDOWS\Programs.txt")
'This is extremely fast, especially if you are dealing with large text files.
    On Error GoTo TextFromFile_Error
    Dim I As Long
    I = FreeFile
    Open fInStream For Input Lock Write As #I
    Screen.MousePointer = vbHourglass
    DoEvents
    TextFromFile = StrConv(InputB$(LOF(I), I), vbUnicode)
    On Error GoTo 0
TextFromFile_Error:
    Close #I
    Screen.MousePointer = vbDefault
End Function