如何刪除vb.net中文本文件末尾的行？

Question

如何確保文件末尾沒有多余的行？ 有點特別，我把一行分成三個地方，分別是17、90和120字節（總共：227字節）。 我試圖用Write替換WriteLine，這很好，但之后我無法編寫新行：我當前的代碼：

 Dim bibliotheque As New article

        With bibliotheque
            .Title = TextBox1.Text
            .Name = TextBox2.Text
            .Charge = TextBox3.Text
        End With

        Dim fileName As String = "c:\essai.librairie"

        Dim fs As FileStream = Nothing
        Try
            fs = New FileStream(fileName, FileMode.Append)
            Using writer As StreamWriter = New StreamWriter(fs)

                writer.WriteLine(bibliotheque.Title.PadRight(17, " "c).ToString & bibliotheque.Name.PadRight(90, " "c).ToString & bibliotheque.Charge.PadRight(120, " "c).ToString)

                ListBox1.Items.Add(bibliotheque.Name)

            End Using

        Finally
            If fs IsNot Nothing Then
                fs.Dispose()
            End If
        End Try

Answer 1

您可以將WriteLine替換為Write ，使用 boolean 變量來了解您是否已添加第一行，如果已添加第一行，請在添加內容之前使用帶有空字符串的WriteLine添加回車符/換行符，像那樣：

    Dim linesExist As Boolean = IO.File.ReadAllLines(fileName).Count > 0
    Try
                fs = New FileStream(fileName, FileMode.Append)
                Using writer As StreamWriter = New StreamWriter(fs)
                    If linesExist Then writer.WriteLine()
                    writer.Write(bibliotheque.Title.PadRight(17, " "c).ToString & bibliotheque.Name.PadRight(90, " "c).ToString & bibliotheque.Charge.PadRight(120, " "c).ToString)
                    ListBox1.Items.Add(bibliotheque.Name)
                End Using
    
            Finally
                If fs IsNot Nothing Then
                    fs.Dispose()
                End If
            End Try

顯然， File.ReadAllLines可能會很慢，您可以使用更優化的方法來檢測文件是否存在並包含內容，但它確實解決了手頭的問題。

Answer 2

Dim fileName As String = "c:\essai.librairie"
Dim bt As New article With {
            .Title = TextBox1.Text,
            .Name = TextBox2.Text,
            .Charge = TextBox3.Text
    }

Using fs As New FileStream(fileName, FileMode.Append)
Using writer As New StreamWriter(fs)
    If fs.Length > 0 Then writer.WriteLine()
    writer.Write($"{bt.Title,-17}{bt.Name,-90}{bt.Charge,-120}")
End Using
End Using
ListBox1.Items.Add(bt.Name)