PART 10 — ファイル操作
FileSystemObject vs Open文・フォルダ再帰処理

Option Explicit

' ── テキスト書き込み ──
Sub WriteTextFile(ByVal path As String, ByVal content As String)
    Dim fn As Integer
    fn = FreeFile   ' 空きファイル番号を取得

    Open path For Output As #fn
    Print #fn, content
    Close #fn
End Sub

' ── テキスト読み込み（全行）──
Function ReadTextFile(ByVal path As String) As String
    Dim fn   As Integer
    Dim line As String
    Dim sb   As String

    fn = FreeFile
    Open path For Input As #fn
    Do While Not EOF(fn)
        Line Input #fn, line
        sb = sb & line & vbCrLf
    Loop
    Close #fn
    ReadTextFile = sb
End Function

Option Explicit

Sub FsoExample()
    Dim fso As Object
    Set fso = CreateObject("Scripting.FileSystemObject")

    Dim srcPath  As String: srcPath  = "C:\data\report.xlsx"
    Dim destPath As String: destPath = "C:\backup\report.xlsx"

    ' ── 存在確認 ──
    If fso.FileExists(srcPath) Then
        ' ── コピー ──
        fso.CopyFile srcPath, destPath

        ' ── 移動 ──
        ' fso.MoveFile srcPath, destPath

        ' ── 削除 ──
        ' fso.DeleteFile srcPath
    End If

    ' ── フォルダ作成 ──
    If Not fso.FolderExists("C:\backup") Then
        fso.CreateFolder "C:\backup"
    End If

    ' ── テキスト書き込み ──
    Dim ts As Object
    Set ts = fso.CreateTextFile("C:\data\log.txt", True, True)  ' True=上書き, True=Unicode
    ts.WriteLine "ログ記録: " & Now
    ts.Close
    Set ts = Nothing

    Set fso = Nothing
End Sub

Option Explicit

' 指定フォルダ以下の xlsx ファイルをすべて収集
Sub CollectXlsxFiles(ByVal folderPath As String, ByRef results As Collection)
    Dim fso    As Object
    Dim folder As Object
    Dim file   As Object
    Dim sub_   As Object

    Set fso    = CreateObject("Scripting.FileSystemObject")
    Set folder = fso.GetFolder(folderPath)

    ' ── ファイルを処理 ──
    For Each file In folder.Files
        If LCase(fso.GetExtensionName(file.Path)) = "xlsx" Then
            results.Add file.Path
        End If
    Next file

    ' ── サブフォルダを再帰処理 ──
    For Each sub_ In folder.SubFolders
        CollectXlsxFiles sub_.Path, results
    Next sub_

    Set fso = Nothing
End Sub

' 呼び出し元
Sub Main()
    Dim results As New Collection
    CollectXlsxFiles "C:\data", results

    Dim item As Variant
    For Each item In results
        Debug.Print item
    Next item
End Sub