＜VB.net＞下CSV文件的导入（读取到DataGridView）和导出（DataGirdView保存到csv）-Toy模板网

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1 创建项目

VB.net项目主要使用微软旗下的Visual Studio 2022编辑器来进行，打开VS2022.新建一个VB.net窗体项目，保存。

然后在窗体上添加以下控件：
DataGridView（数据表格控件）、Label（标签控件）、ContextMenuStrip（右键关联菜单控件）等
＜VB.net＞下CSV文件的导入（读取到DataGridView）和导出（DataGirdView保存到csv）
然后，设置DataGridView控件的contextmenustrip属性（关联到添加的contextmenustrip控件上）。

2 编写程序

由于需要读取csv文档，所以需要添加一些namespace。

2.1 导入namespace

Imports System.IO
Imports System.Text
Imports CsvHelper

上面的namespace中，system.IO是windows用于读取流数据的类，而CsvHelper是一个.NET程序包，其封装了.net的文本读取类textreader，提供便捷的处理csv文档api接口。

2.2 cvs文件导入

使用streamreader读取csv为流数据，使用csvhelper提供的函数，获取一个idatareader的实例（datatable数据格式），再新建一个datatable，使用load加载csv的数据，然后将datatable的数据添加到datagridview控件上，或者直接使用DataSource绑定datatable（不过我用这个方法，读取的csv数据无法编辑，暂时不清楚原因）

Private Sub import_csv(fl As String)



        Dim strd1 As StreamReader = Nothing

        Try

            strd1 = New StreamReader(fl, Encoding.GetEncoding("gb2312"))    '中文编码gb2312

            Dim csv = New CsvReader(strd1, CultureInfo.InvariantCulture)

            Dim dr = New CsvDataReader(csv)

            Dim dt = New DataTable()

            dt.Load(dr)

            DataGridView1.Rows.Clear()

            For i = 0 To dt.Rows.Count - 1

                Dim inx0 = DataGridView1.Rows.Add()

                For j = 0 To dt.Columns.Count - 1


                    DataGridView1.Columns(j).HeaderText = dt.Columns(j).ToString()

                    DataGridView1.Rows(i).Cells(j).Value = dt.Rows(i).Item(j).ToString()

                Next

            Next


            strd1.Dispose()

            csv.Dispose()

            dr.Dispose()

            dt.Dispose()


        Catch ex As Exception

            MsgBox(ex.Message, MsgBoxStyle.OkOnly, "tip!")

        Finally

            strd1.Close()

        End Try

    End Sub

2.2 导出csv

由于表格数据中，数据都是在单元格中，所以，将datagridview中的数据导出为csv，就是把单元格的数据一一对应赋值即可。
同样是使用流数据操作，首先打开一个已存在的csv文档或者新建一个（文件路径），然后获取文件的流（stream），使用streamwriter，将数据写入流中（也就是写入csv文件中），完成后记得释放资源（dispose）。
其中麻烦一点的，是需要算一下datagridview的单元格与csv文档的单元是如何一一对应的，不过，这种程序网上很多，不需要自己花费时间去计算，按照网上的程序，自己修改一下即可。

 Private Sub export_csv(dgv As DataGridView, s1 As Stream)

        Using sw1 As New StreamWriter(s1, Encoding.Default)

            Dim columntitle As String = ""
            Try
                For i As Integer = 0 To dgv.ColumnCount - 1
                    If i > 0 Then
                        columntitle += ","
                    End If
                    columntitle += dgv.Columns(i).HeaderText
                Next

                columntitle.Remove(columntitle.Length - 1)
                sw1.WriteLine(columntitle)

                For j As Integer = 0 To dgv.Rows.Count - 1
                    Dim columevalue As String = ""
                    For k As Integer = 0 To dgv.Columns.Count - 1

                        If k > 0 Then
                            columevalue += ","
                        End If

                        If dgv.Rows(j).Cells(k).Value Is Nothing Then
                            columevalue += ""
                        Else
                            Dim m As String = dgv.Rows(j).Cells(k).Value.ToString().Trim()
                            columevalue += m.Replace(",", ", ")
                        End If

                    Next

                    columevalue.Remove(columevalue.Length - 1)
                    sw1.WriteLine(columevalue)

                Next
                sw1.Close()
                s1.Close()


            Catch ex As Exception

            Finally
                sw1.Close()
                s1.Close()

            End Try

        End Using


    End Sub

3 说明

这个例子没有测试过大量数据的csv文档的读取，只是提供了一个实现的方法。如果是那种有大量数据的读写，应该需要多线程来实现（将文件分割读取，否则加载时应该会等很久）。

演示视频：

vb.net下csv导入导出演示

完整代码：文章来源地址https://www.toymoban.com/news/detail-447698.html


Imports System.Windows.Forms.DataVisualization.Charting
Imports System.IO
Imports System.Text
Imports CsvHelper
Imports System.Globalization
Public Class Form9

    Public series1 As Series
    Public caiyang_num As Integer
    Public caiyang_time As Integer
    Private Sub Form9_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        Me.Text = "表格浏览器"

        DataGridView1.Columns.Add("col1", "X 坐标(100ms)")
        DataGridView1.Columns.Add("col2", "Y 坐标（mm/10000）")

        For i = 0 To DataGridView1.Columns.Count - 1

            DataGridView1.Columns(i).SortMode = DataGridViewColumnSortMode.NotSortable     '列的排序模式

        Next

        If series1 IsNot Nothing Then
            chart_data_show(series1)
        End If
        Label8.Text = caiyang_num.ToString() & "个"
        Label9.Text = caiyang_time.ToString() & "ms"

    End Sub

    Private Sub chart_data_show(s1 As Series)

        For i = 0 To s1.Points.Count - 1

            Dim inx0 = DataGridView1.Rows.Add()

            DataGridView1.Rows(inx0).SetValues(s1.Points(i).XValue.ToString())
            DataGridView1.Rows(inx0).Cells(1).Value = s1.Points(i).YValues(0).ToString()

        Next

        caiyang_num = s1.Points.Count

    End Sub


    Private Sub 导入数据CSVToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles 导入数据CSVToolStripMenuItem.Click


        OpenFileDialog1.Filter = "CSV(逗号分隔)(*.csv)|*.csv|文本文件(*.txt)|*.txt|所有文件 (*.*)|*.*"
        OpenFileDialog1.InitialDirectory = "C:\User\rongjv\Desktop\"
        OpenFileDialog1.RestoreDirectory = True

        Dim fl As String = Nothing
        If OpenFileDialog1.ShowDialog = DialogResult.OK Then

            fl = OpenFileDialog1.FileName

            Dim fi1 = New FileInfo(fl)

            If fi1.Length > 1048576 Then
                Label5.Text = String.Format("{0,10:#.0000}", fi1.Length / 1024 / 1024) & "MB"
            Else
                Label5.Text = String.Format("{0,10:#.0000}", fi1.Length / 1024) & "KB"
            End If

            Label3.Text = fl

            import_csv(fl)

        End If




    End Sub

    Private Sub 导出数据CSVToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles 导出数据CSVToolStripMenuItem.Click

        Dim st1 As Stream = Nothing

        SaveFileDialog1.Filter = "CSV(逗号分隔)(*.csv)|*.csv|文本文件(*.txt)|*.txt|所有文件 (*.*)|*.*"
        SaveFileDialog1.InitialDirectory = "C:\User\rongjv\Desktop\"
        SaveFileDialog1.RestoreDirectory = True


        If SaveFileDialog1.ShowDialog = DialogResult.OK Then



            st1 = SaveFileDialog1.OpenFile()

            Label4.Text = SaveFileDialog1.FileName

            export_csv(DataGridView1, st1)

            st1.Dispose()

        End If

    End Sub

    Private Sub import_csv(fl As String)



        Dim strd1 As StreamReader = Nothing

        Try

            strd1 = New StreamReader(fl, Encoding.GetEncoding("gb2312"))    '中文编码gb2312

            Dim csv = New CsvReader(strd1, CultureInfo.InvariantCulture)

            Dim dr = New CsvDataReader(csv)

            Dim dt = New DataTable()

            dt.Load(dr)

            DataGridView1.Rows.Clear()

            For i = 0 To dt.Rows.Count - 1

                Dim inx0 = DataGridView1.Rows.Add()

                For j = 0 To dt.Columns.Count - 1


                    DataGridView1.Columns(j).HeaderText = dt.Columns(j).ToString()

                    DataGridView1.Rows(i).Cells(j).Value = dt.Rows(i).Item(j).ToString()

                Next

            Next


            strd1.Dispose()

            csv.Dispose()

            dr.Dispose()

            dt.Dispose()


        Catch ex As Exception

            MsgBox(ex.Message, MsgBoxStyle.OkOnly, "tip!")

        Finally

            strd1.Close()

        End Try

    End Sub

    Private Sub export_csv(dgv As DataGridView, s1 As Stream)

        Using sw1 As New StreamWriter(s1, Encoding.Default)

            Dim columntitle As String = ""
            Try
                For i As Integer = 0 To dgv.ColumnCount - 1
                    If i > 0 Then
                        columntitle += ","
                    End If
                    columntitle += dgv.Columns(i).HeaderText
                Next

                columntitle.Remove(columntitle.Length - 1)
                sw1.WriteLine(columntitle)

                For j As Integer = 0 To dgv.Rows.Count - 1
                    Dim columevalue As String = ""
                    For k As Integer = 0 To dgv.Columns.Count - 1

                        If k > 0 Then
                            columevalue += ","
                        End If

                        If dgv.Rows(j).Cells(k).Value Is Nothing Then
                            columevalue += ""
                        Else
                            Dim m As String = dgv.Rows(j).Cells(k).Value.ToString().Trim()
                            columevalue += m.Replace(",", ", ")
                        End If

                    Next

                    columevalue.Remove(columevalue.Length - 1)
                    sw1.WriteLine(columevalue)

                Next
                sw1.Close()
                s1.Close()


            Catch ex As Exception

            Finally
                sw1.Close()
                s1.Close()

            End Try

        End Using


    End Sub

    Private Sub 清空数据ToolStripMenuItem1_Click(sender As Object, e As EventArgs) Handles 清空数据ToolStripMenuItem1.Click

        DataGridView1.Rows.Clear()

    End Sub
End Class