StreamReaderでClose、Disposeしたはずが

        Dim sr As StreamReader

        Try
            sr = New StreamReader(sDataPath, Encoding.GetEncoding(932))

            Try
                ' 読み込みできる文字がなくなるまで繰り返す
                While (sr.Peek() >= 0)

                    ' ファイルを 1 行ずつ読み込む
                    sData = sr.ReadLine()

                    ' 〜処理〜

                End While

            Finally
                If Not sr Is Nothing Then
                    sr.Close()
                End If

            End Try
        Finally
            If Not sr Is Nothing Then
                Dim hDisposable As IDisposable = sr
                hDisposable.Dispose()
            End If

        End Try

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

        Dim r As IO.StreamReader = Nothing

        Try
            r = New IO.StreamReader("c:\temp\test.txt")

            Do While Not r.EndOfStream
                r.ReadLine()
            Loop

            r.Close()

        Catch ex As Exception
        Finally
            r.Dispose()
        End Try


    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

        Dim w As New IO.StreamWriter("c:\temp.test.txt", True)
        w.Close()
        w.Dispose()

    End Sub