Imports System.Data.SqlClient
Imports System.Data
...
Function csv2Datatable(ByVal Dateiname As String) As DataTable
 
    If System.IO.File.Exists(Dateiname) = False Then Return Nothing
 
    Dim FileInfo As System.IO.FileInfo = New System.IO.FileInfo(Dateiname)
    Dim DT As New DataTable
    Dim oConn As SqlConnection = New SqlConnection
    If Dateiname.Contains(".xlsx") Then
        oConn.ConnectionString = ("Provider=Microsoft.ACE.OLEDB.12.0;Data" & _
          "Source=" & Dateiname & ";Extended Properties=" & Chr(34) & "Excel" & _
          "12.0 Xml;HDR=YES" & Chr(34) & ";")
    Else
        oConn.ConnectionString = ("Provider=MSDASQL; Driver={Microsoft Excel" & _
          "Driver (*.xls)}; DBQ=" & Dateiname & ";")
    End If
    oConn.Open()
    Dim da As SqlDataAdapter = New SqlDataAdapter(String.Format("select * from" & _
      "[{0}]", Dateiname), oConn)
    da.Fill(DT)
    oConn.Close()
    Return DT
 
End Function