Question

Vb.net存csv文件，文件被打开后，再用程序存储就会存存不进去

Answer 1

参考
Private Function ExportCsvProcess
　　(ByVal FilePath As String ByVal,
　　dt As DataTable) As Boolean
　　Dim fileStream As System.IO.FileStream
　　Dim streamWriter As System.IO.StreamWriter
　　Dim intRow, intCol As Integer
　　Dim strRow As String
　　'删除旧CSV文件
　　If (System.IO.File.Exists(FilePath)) Then
　　System.IO.File.Delete(FilePath)
　　End If
　　Try
　　fileStream = New FileStream(FilePath,
　　System.IO.FileMode.CreateNew, System.IO.
　　FileAccess.Write)
　　If Not dt Is Nothing Then
　　streamWriter = New StreamWriter
　　(fileStream, System.Text.Encoding.Default)
　　strRow = ""
　　'读列名
　　For intCol = 0 To dt.Columns.Count - 1
　　strRow += dt.Columns(intCol).ColumnName
　　If intCol <dt.Columns.Count - 1 Then
　　strRow += ","
　　End If
　　Next
　　streamWriter.WriteLine(strRow)
　　'读每行的值
　　For intRow = 0 To dt.Rows.Count - 1
　　strRow = ""
　　For intCol = 0 To dt.Columns.Count - 1
　　strRow += CStr(dt.Rows(intRow).Item(intCol))
　　If intCol <dt.Columns.Count - 1 Then
　　strRow += ","
　　End If
　　Next
　　streamWriter.WriteLine(strRow)
　　Next
　　streamWriter.Close()
　　End If
　　Catch ex As Exception
　　MessageShow(ex.ToString())
　　Return False
　　Finally
　　fileStream.Close()
　　End Try
　　Return True
　　End Function
　　必要时可以进行特殊字符的过滤
　　VB.NET操作CSV文件中特殊字符的过滤
　　Private Function DelSpacChr
　　(ByVal str As String) As String
　　Dim i As Integer
　　Dim result As String = str
　　Dim strSpac() As String =
　　{"~", "!", "@", "#", "$", "%",
　　"^", "&", "*", "(", ")", "`", ";",
　　"'", ",", ".", "/", ":", "/,",
　　"<", ">", "?"}
　　For i = 0 To i <strSpac.Length
　　If result.IndexOf(strSpac(i)) > -1 Then
　　resultresult = result.Replace
　　(strSpac(i), "")
　　End If
　　Next
　　Return result
　　End Function
　　下面是从CSV导入到DataTable，当然还可以像上面一样使用文件流操作，但这里采用OLEDB类实现VB.NET操作CSV文件。
　　Public Function CSVToDataTable(ByVal
　　FilePath As String) As DataTable
　　Try
　　If (System.IO.File.Exists(FilePath)) Then
　　Dim fi As New System.IO.FileInfo(FilePath)
　　'HDR=NO 第一行当数据处理
　　'HDR=YES(默认）第一行当列处理
　　Dim sConnectionString As String =
　　"Provider=Microsoft.Jet.OLEDB.4.0;
　　Extended Properties='Text;HDR=NO';Data
　　Source=" & fi.DirectoryName
　　Dim objConn As New System.Data.OleDb.
　　OleDbConnection(sConnectionString)
　　objConn.Open()
　　Dim strColum As String
　　Dim objCmdSelect As New Data.OleDb.
　　OleDbCommand("SELECT Distinct * FROM "
　　& fi.Name, objConn)
　　Dim objAdapter As New Data.OleDb.
　　OleDbDataAdapter
　　Dim dt As New DataTable objAdapter.
　　SelectCommand = objCmdSelect
　　objAdapter.Fill(dt) objConn.Close()
　　Return dt
　　End
　　If Catch ex As Exception
　　MessageShow(ex.ToString())
　　Return Nothing
　　End Try
　　End Function
　　OK，VB.NET操作CSV文件完毕。