如何解决如何在 vb.net 中从下到上浏览文本文件?
我无法让下面的代码正常工作,事实上我想按一个后退按钮以逐行向上移动一个文本文件,然后我将链切成 3 部分。
Dim LinesOfText() As String = System.IO.File.ReadAllLines("c:\essai.librairie",Encoding.UTF8)
For line As Integer = LinesOfText.Length - 1 To 0 Step -1
Dim currentLine As String = LinesOfText(line)
Dim value As String = currentLine
Dim startIndex As Integer = 0
Dim length As Integer = 17
Dim substring As String = value.Substring(startIndex,length)
Dim subs As String = value.Substring(17,90)
Dim subst As String = value.Substring(107,120)
TextBox1.Text = substring
TextBox2.Text = subs
TextBox3.Text = subst
Next
解决方法
如果您将行和行计数器存储在需要的范围内,您可以这样做:
Imports System.IO
Public Class Form1
Dim lines As String()
Dim currentLine As Integer = -1
Sub LoadData(filename As String)
lines = File.ReadAllLines(filename)
currentLine = lines.Length - 1
End Sub
Sub ShowCurrentLine()
If currentLine >= 0 Then
TextBox1.Text = lines(currentLine).Substring(0,3)
TextBox2.Text = lines(currentLine).Substring(4,3)
TextBox3.Text = lines(currentLine).Substring(8,3)
lblLineNo.Text = (currentLine + 1) & "/" & lines.Length
Else
TextBox1.Clear()
TextBox2.Clear()
TextBox3.Clear()
lblLineNo.Text = "-"
End If
End Sub
Private Sub bnNext_Click(sender As Object,e As EventArgs) Handles bnNext.Click
If currentLine < lines.Length - 1 Then
currentLine += 1
ShowCurrentLine()
End If
End Sub
Private Sub bnPrev_Click(sender As Object,e As EventArgs) Handles bnPrev.Click
If currentLine > 0 Then
currentLine -= 1
ShowCurrentLine()
End If
End Sub
Private Sub Form1_Load(sender As Object,e As EventArgs) Handles MyBase.Load
LoadData("C:\temp\SO67209265.txt")
ShowCurrentLine()
End Sub
End Class
您需要为数据设置子字符串参数(我只使用了一个小文本文件)以及要加载的文件名。
标签 lblLineNo
用于显示当前行号,从 1 开始。
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