如何删除vb.net中文本文件末尾的行？

Question

如何确保文件末尾没有多余的一行？有点特殊，我把一行分成了三个地方，分别是17、90、120字节（共227字节）。我尝试用 Write 替换 WriteLine，没问题，但之后我不能写新行了！我当前的代码：

 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

您可以将 WriteLine 替换为 Write，使用布尔变量来了解您是否已经添加了第一行，如果已经添加了第一行，则只添加回车符 return/line 在添加内容之前使用带有空字符串的 WriteLine 进行提要，例如：

    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

显然，File.ReadAllLines可能会很慢，您可以使用更优化的方法来检测文件是否存在以及是否有内容，但它确实解决了手头的问题。

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)

如何删除vb.net中文本文件末尾的行？

How to delete the line at the end of the text file in vb.net?

vb.net

filestream

streamwriter