vb.net怎么读写文本指定字符之间的行

窗体上一个button，一个textbox，我用的是visual studio 2010
Public Class Form1

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click’将与程序同文件夹的1.txt中的数据读取出来，并找到内容中textbox1输入的那条记录，进行输出，如果没找到返回空
MsgBox(GetInf(InputTxt(Application.StartupPath + "\1.txt"), Val(TextBox1.Text)))
End Sub

Private Function GetInf(ByVal txt As String, ByVal Num As Integer) As String’在指定的txt内容中，查找指定编号的记录
Dim tt As String = "", s As String
Dim L1 As Integer = Len(txt)
Dim i As Integer
Dim doCopy As Boolean = False
For i = 1 To L1
s = Mid(txt, i, 3)
If s = " " + Num.ToString + " " Or s = vbCrLf + Num.ToString Then
doCopy = True
i += 3
Continue For
End If
If s = " " + (Num + 1).ToString + " " Or s = vbCrLf + (Num + 1).ToString Then Exit For
If doCopy Then
s = Mid(txt, i, 1)
tt += s
End If
Next
Return tt
End Function

Private Function InputTxt(ByVal path As String) As String‘读取指定位置的文件并且将内容返回
Dim temp As String = "", tt As String = " "
FileOpen(1, path, OpenMode.Input, OpenAccess.Read)
Do Until EOF(1)
Input(1, temp)
tt += temp + vbCrLf
Loop
FileClose()
Return tt
End Function
End Class
希望能帮到你

太深奥了。

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