C# と VB.NET の質問掲示板

※削除ファイルを考慮していなかったので処理追加
Module Module1
    Private checkPath As Dictionary(Of String, Date) = New Dictionary(Of String, Date)
    Public Sub ClserCheckPath()
        checkPath = New Dictionary(Of String, Date)
    End Sub
    Public Function StartCheckPath(path As String) As Boolean
        Dim IsChange As Boolean = False
        Dim temp As Dictionary(Of String, String) = New Dictionary(Of String, String)

        Dim di As New System.IO.DirectoryInfo(path)
        Dim files As System.IO.FileInfo() = di.GetFiles("*", System.IO.SearchOption.AllDirectories)
        For Each f As System.IO.FileInfo In files
            Dim fullPath As String = f.FullName
            f.Refresh()
            If checkPath.ContainsKey(fullPath) Then
                If checkPath(fullPath) <> f.LastWriteTime Then
                    checkPath(fullPath) = f.LastWriteTime
                    IsChange = True
                End If
            Else
                checkPath.Add(fullPath, f.LastWriteTime)
                IsChange = True
            End If
            temp.Add(fullPath, fullPath)
        Next
        '削除ファイル確認
        Dim keys() As String = checkPath.Keys.ToArray
        For Each key As String In keys
            If temp.ContainsKey(key) = False Then
                IsChange = True
                checkPath.Remove(key)
            End If
        Next
        Return IsChange
    End Function
End Module

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Call ClserCheckPath()
    'ストップウォッチを開始する 
    Dim sw As New System.Diagnostics.Stopwatch()
    sw.Start()

    Debug.Print("{0}", StartCheckPath("D:\Test\"))

    'ストップウォッチを止め結果を表示する 
    sw.Stop()
    Debug.Print("{0}", sw.Elapsed)

    '一秒間（1000ミリ秒）停止するこの間に変更があるものとする
    System.Threading.Thread.Sleep(1000)

    sw.Start()

    Debug.Print("{0}", StartCheckPath("D:\Test\"))

    'ストップウォッチを止め結果を表示する 
    sw.Stop()
    Debug.Print("{0}", sw.Elapsed)
End Sub