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我希望能够通过管道（“|”）分隔的文本文件移动，控制我读取的行和列。

我以前在 MS Access VBA 中实现了这一点，目前正在 VB.NET 中开始，但正在努力完成这一点。

在 Access 中，VBA 允许我以记录集 ( Dim rs As DAO.Recordset) 的形式链接到文本文件，预定义为分隔并在行中移动 (rs.MoveNext或rs.MovePrevious)，同时选择我需要的字段/列 ( rs!Field1)。

VB.NET 中是否有任何等价物？到目前为止，我只能从 MSDN 中找到以下内容，但不知道如何操作它：

    Using MyReader As New Microsoft.VisualBasic.FileIO.TextFieldParser(FName)

        MyReader.TextFieldType = FileIO.FieldType.Delimited
        MyReader.SetDelimiters("|")
        Dim currentrow As String()

        While Not MyReader.EndOfData

            currentrow = MyReader.ReadFields()
            Dim currentfield As String
            For Each currentfield In currentrow
                MsgBox(currentfield)
            Next

        End While

    End Using

我希望能够将某些字段存储到稍后写入 .CSV 文件的变量中。

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1 回答 1

1

对于这可能会有所帮助的任何人，我在以下两个网站的帮助下设法解决了这个问题：

循环遍历目录中的文件

分隔数据

使用这些我创建了以下按钮单击子和随附功能：

Private Sub Button_Run_Click(sender As Object, e As EventArgs) Handles Button_Run.Click

    ' Make a reference to a directory
    Dim strDir As String = ("C:\")
    Dim Dir As New System.IO.DirectoryInfo(strDir)

    ' Get a reference to each file in that directory
    Dim fiArr As System.IO.FileInfo() = Dir.GetFiles()

    Dim fri As System.IO.FileInfo

    'For each file call the formatter to write to a text file
    'Then delete each file after writing it
    For Each fri In fiArr
        Call Formatter(strDir & fri.Name)
        My.Computer.FileSystem.DeleteFile(strDir & fri.Name)
    Next fri

End Sub

然后我用分隔符分割每一行，每个字段都可以获得（使用values(0)定义的变量）和修改（使用它的索引）。i控制线就像使用或通过更改整数来修改现有变量来创建新变量一样简单。例如：

Dim Nvalues() As String = lines(i + 1).Split("|")

使用它我创建了以下函数：

Public Sub Formatter(ByVal FName As String)

    'Standard start defining stream reader to loop
    'through and pull data from text files
    'FName is provided from the form button sub
    Dim StrReader As New System.IO.StreamReader(FName)

    Dim text As String = StrReader.ReadToEnd

    StrReader.Close()

    Dim lines() As String = text.Split(vbLf)

    'Define all variables that may need to be stored before writing
    Dim x1, x2, x3, x4, x5, x6, x7, x8, x9, x0 As String

    'Define where the data will be written to (line by line)
    Dim FPath As String = "C:\Sample.txt"
    If Not System.IO.File.Exists(FPath) Then
        System.IO.File.Create(FPath).Dispose()
    End If
    Dim objwriter As System.IO.StreamWriter

    'Set loop to go through all data from beginning to end using i as line index
    Dim i As Double
    For i = 0 To lines.Length - 1

        'Split each line by pipes (|) allowing "values" to be indexed to pull by column
        Dim values() As String = lines(i).Split("|")

        'Set 1st column in row as switch item
        Select Case values(0)

            'If 1st column in row is 001, store required data in variables
            'specified using the index of the value to give accurate column
            Case "001"
                x1 = values(1)
                x2 = values(2)
                x3 = values(3)
                x3 = values(4)

                'Repeat same as 001 but for 002
            Case "002"
                x4 = values(1)
                x5 = values(2)

                'Repeat same as 001 but for 003
            Case "003"
                x6 = values(1)
                x7 = values(2)

                'Write to file including fields 1 & 3 from 004 group
            Case "004"

                objwriter = System.IO.File.AppendText(FPath)
                objwriter.WriteLine(x1 & "," & x2 & "," & x3 & "," & x4 _
                    & "," & x5 & "," & x6 & "," & x7 & "," _
                    & Nvalues(1) & "," & Nvalues(2))
                objwriter.Close()

            Case Else

        End Select

        Application.DoEvents()

    Next

End Sub
于 2017-03-06T09:01:21.743 回答