从 VB.NET 中的文本文件导入数据

Question

所以，我正在尝试开发一个图书数据库。我创建了一个包含 11 列的 table 来填充 DGV，其中仅显示 6 列。每本书的完整数据显示在表格的下半部分，其中我有文本框，这些文本框与 table 绑定 (BindingSource)，随着我在 DGV 中的移动而变化。

现在，我想做的是能够从文件中获取 export/import 数据。

我已经用下面的代码完成了导出部分：

Private Sub BtnExport_Click(sender As Object, e As EventArgs) Handles BtnExport.Click

Dim txt As String = String.Empty

For Each row As DataGridViewRow In DbdocsDataGridView.Rows
            For Each cell As DataGridViewCell In row.Cells
                'Add the Data rows.
                txt += CStr(cell.Value & ","c)
            Next

            'Add new line.
            txt += vbCr & vbLf
        Next

Dim folderPath As String = "C:\CSV\"
        File.WriteAllText(folderPath & "DataGridViewExport.txt", txt)

    End Sub

但是，我无法从 txt 导入。我试过的是：https://1bestcsharp.blogspot.com/2018/04/vb.net-import-txt-file-text-to-datagridview.html 如果您对 table 进行编码并且它可以毫无问题地填充 de DGV，则它会完美运行。我看不出应该如何调整该代码以满足我的需要。

Private Sub BtnImport_Click(sender As Object, e As EventArgs) Handles BtnImport.Click

        DbdocsDataGridView.DataSource = table

        Dim filas() As String
        Dim valores() As String

        filas = File.ReadAllLines("C:\CSV\DataGridViewExport.txt")

        For i As Integer = 0 To filas.Length - 1 Step +1

            valores = filas(i).ToString().Split(",")

            Dim row(valores.Length - 1) As String

            For j As Integer = 0 To valores.Length - 1 Step +1
                row(j) = valores(j).Trim()

            Next j

            table.Rows.Add(row)
        Next i

    End Sub

这是我迄今为止尝试过的方法，但我总是会出现异常。

提前感谢任何能给我一些见解的人。

Answer 1

这是写入文本文件的代码：

speichern 表示 to save。请注意，出于格式原因，我在示例中使用了 #。再次阅读时，您可以找到 # 然后您就知道那一行即将到来...... 我使用 Private ReadOnly Deu As New System.Globalization.CultureInfo("de-DE") 将日期格式化为德语格式，但您可以自行决定是否需要。请注意，我使用的是从 Visual Studio 自己的 NuGet 包管理器下载的 FileDialog。

Private Sub Button_speichern_Click(sender As Object, e As EventArgs) Handles Button_speichern.Click
        speichern()
    End Sub

    Private Sub speichern()
        '-------------------------------------------------------------------------------------------------------------
        ' User can choose where to save the text file and the program will save it .
        '-------------------------------------------------------------------------------------------------------------
        Dim Path As String
        Using SFD1 As New CommonSaveFileDialog
            SFD1.Title = "store data in a text file"
            SFD1.Filters.Add(New CommonFileDialogFilter("Textdatei", ".txt"))
            SFD1.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
            If SFD1.ShowDialog() = CommonFileDialogResult.Ok Then
                Path = SFD1.FileName & ".txt"
            Else
                Return
            End If
        End Using

        Using textfile As System.IO.StreamWriter = My.Computer.FileSystem.OpenTextFileWriter(Path, True, System.Text.Encoding.UTF8)
            textfile.WriteLine("Timestamp of this file [dd.mm.yyyy hh:mm:ss]: " & Date.Now.ToString("G", Deu) & NewLine & NewLine) 'supposed to be line break + 2 blank lines :-)
            
            
                
                    textfile.WriteLine("your text")
                    textfile.WriteLine("#") 'Marker
            
            textfile.Close()
        End Using
    End Sub

    Private Sub FormMain_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
        speichern()
    End Sub

这是从文本文件中读取：

'read all Text
        Dim RAT() As String = System.IO.File.ReadAllLines(Pfad, System.Text.Encoding.UTF8)

        If RAT.Length = 0 Then Return Nothing

        For i As Integer = 0 To RAT.Length - 1 Step 1
            If RAT(i) = "#" OrElse RAT(i) = "" Then Continue For
            'do your work here with (RAT(i))
        Next

Answer 2

DataTable class 具有 load/save 数据 from/to XML 的内置方法，称为 ReadXml 和 WriteXml。看一下使用重载来保留架构的示例：

Private ReadOnly dataGridViewExportPath As String = IO.Path.Combine("C:\", "CSV", "DataGridViewExport.txt")
Private Sub BtnExport_Click(sender As Object, e As EventArgs) Handles BtnExport.Click
    table.WriteXml(path, XmlWriteMode.WriteSchema)
End Sub

Private Sub BtnImport_Click(sender As Object, e As EventArgs) Handles BtnImport.Click
    table.ReadXml(path)
End Sub

虽然用户可以手动编辑由 WriteXML 生成的 XML 文件，但我当然不建议这样做。

从 VB.NET 中的文本文件导入数据

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