Question

我有一个文本文件（其主机文件）我可以通过文本框将线（域）添加到文件中。当我单击“保存”按钮时，输入的值（域）将以127.0.0.1前缀保存到文本（主机）文件中。同时它也在列表框中显示（在列表框中显示时，它不会显示前缀（127.0.0.1）。它只会显示从文本字段中获得的值）

我现在需要的是

当我单击并从列表框中选择一个项目并按“删除”按钮时，需要将其从列表框和文本（主机）文件中删除。

此外，在从列表框中删除所选项目时，还应从文件中删除前缀（127.0.0.1），而不能留空行。

Private Sub Button6_Click(sender As Object, e As EventArgs) Handles BtnCustomDomainremove.Click
        ListBox1.Items.Remove(ListBox1.SelectedItem)
        Dim delLine As Integer = 1
        Dim lines As List(Of String) = System.IO.File.ReadAllLines("C:\Windows\System32\drivers\etc\hosts").ToList
        lines.RemoveAt(delLine - 1)
        System.IO.File.WriteAllLines("C:\Windows\System32\drivers\etc\hosts", lines)
        MessageBox.Show("URL removed from Block List !", "Custom Block List")
End Sub

上面的代码将文件中的最高值删除，并从列表框中选择一个值。

Answer 1

   Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim lines As List(Of String) = System.IO.File.ReadAllLines("C:\Windows\System32\drivers\etc\hosts").ToList
    Dim Findstring = IO.File.ReadAllText("C:\Windows\System32\drivers\etc\hosts")
    Dim Lookfor As String = CStr("127.0.0.1" + ListBox1.SelectedItem)

    If lines.Contains(Lookfor) Then
        For i = 0 To Findstring.Length - 1
            lines.Remove(Lookfor)
        Next
        System.IO.File.WriteAllLines("C:\Windows\System32\drivers\etc\hosts", lines)
        ListBox1.Items.Remove(ListBox1.SelectedItem)
        MessageBox.Show("URL removed from Block List !", "Custom Block List")
    Else
        MsgBox("string not found")
    End If
End Sub

此代码对我有用，您可能需要对其稍加调整以匹配您的喜好，但是，似乎发现listbox1中所选项目的每一次出现（如果有多个）（如果只有一个）发生时，您可以删除for循环。

Answer 2

代替对列表的每次更改读取和写入文件，在窗体关闭时保存列表。表单打开时读取文件并填充列表。打开表单后，只需照常添加和删除列表项即可。

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Dim path = "C:\Windows\System32\drivers\etc\hosts.txt"
    Dim lines() As String = File.ReadAllLines(path)
    'Substring(9) the characters in "127.0.0.1" are index 0-8 so we begin with index 9
    'and return the rest of the string.
    Dim TrimmedList = From line In lines
                      Select line.Substring(9)
    For Each item In TrimmedList
        ListBox2.Items.Add(item)
    Next
End Sub

Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
    Dim sb As New StringBuilder()
    For Each item In ListBox2.Items
        sb.AppendLine("127.0.0.1" & item.ToString)
    Next
    Dim path = "C:\Windows\System32\drivers\etc\hosts.txt"
    File.WriteAllText(path, sb.ToString)
End Sub

需要

Imports System.IO
Imports System.Text

Answer 3

尝试此代码

Private Sub Button6_Click(sender As Object, e As EventArgs) Handles BtnCustomDomainremove.Click
        ListBox1.Items.Remove(ListBox1.SelectedItem)
        Dim details As String = ""
        For Each o As Object In ListBox1.Items
            details += o.ToString + vbNewLine
        Next
        My.Computer.FileSystem.WriteAllText("C:\Windows\System32\drivers\etc\hosts", details, False)
        MessageBox.Show("URL removed from Block List !", "Custom Block List")
End Sub

从列表框中列出的文本文件中删除行

3 个答案: