@大卫发布了一个完整快速的csv搜索方法：无论如何，这是一个“手动”和缓慢的方法来理解基本的阅读和搜索csv文件：（注意，字段内容中的分隔符将导致随机行为）

Imports System.IO

Public Class CSV
    Private Sub scanCSV()
        Dim sr As New StreamReader("d:\files\file.csv") 'useful method to read any strings file
        Dim lineNum As Integer
        sr.ReadLine() 'rem this line if your file has no header
        While Not sr.EndOfStream ' stop loop when file eof
            Dim line As String = sr.ReadLine() 'read entire line
            For Each str As String In line.Split(",") 'split cut line into separated parts - separator =","
                If IsDate(str) Then 'vb function to test if string is a valid date
                    'date found
                    MsgBox("date found in line N°" & lineNum & " date = " & str)
                End If
            Next
            lineNum += 1 'increment line number
        End While
 end sub
end class

第一步是将CSV文件加载到内存中。您可以使用OleDb提供程序将CSV文件加载到DataTable（documentation）中，如下所示：https://stackoverflow.com/a/11120351/1920035
下一步是查询数据。DataTable类提供了Select方法（documentation），该方法允许您传递筛选表达式。要按日期值筛选，请将日期文字用磅号括起来，例如#2023-02-27#。
最后一步是显示数据，但由于您在最初的帖子中没有提供足够的信息，我无法帮助您完成这一步。
以下是所有这些信息的汇总：

Private Function LoadCsv(path As String) As DataTable
    Dim folder = IO.Path.GetDirectoryName(path)
    Dim filename = IO.Path.GetFileName(path)
    Dim connection = $"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={folder};Extended Properties=""text;HDR=No;FMT=Delimited"";"
    Dim csv = New DataTable

    Using adapter = New OleDbDataAdapter($"select * from [{filename}]", connection)
        adapter.Fill(csv)
    End Using

    Return csv
End Function

Private Function FilterOnOrBeforeDate(csv As DataTable, column As String, value As DateTime) As DataRow()
    Return csv.Select($"{column} <= #{value}#")
End Function