Привести VBA модуль Function на VB.NET

Option Compare Database
Option Explicit
 
Public Function JoinStrOnGrp7(on_id As Integer) As String
 
Dim db As Database
Dim rs As Recordset
 
Set db = CurrentDb()
Set rs = db.OpenRecordset("SELECT [Предмет] FROM [t7] WHERE [ID]=" & Str(on_id))
JoinStrOnGrp7 = ""
Do While Not rs.EOF
   If JoinStrOnGrp7 <> "" Then JoinStrOnGrp7 = JoinStrOnGrp7 + ","
   JoinStrOnGrp7 = JoinStrOnGrp7 + Nz(rs![Предмет], "                                      ")
   rs.MoveNext
Loop
 
End Function

    Sub conn1()
        Dim Con As New OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=1234.mdb")
        Dim stSQL As String
 
        'stSQL = "SELECT t7.ID, t7.student.Name AS ФИО, t7.klass.Name AS Класс, t7.data_ocen AS Дата, " & JoinStrOnGrp7("id") & " AS Сообшение FROM t7 GROUP BY t7.ID, t7.student.Name, t7.klass.Name, t7.data_ocen, " & JoinStrOnGrp7("id") & " HAVING (((t7.data_ocen)=Date())) ORDER BY t7.student.Name;"
 
        stSQL = "SELECT t7.ID, t7.student.Name AS ФИО, t7.klass.Name AS Класс, t7.data_ocen AS Дата, t7.student.Name AS Сообшение FROM t7 GROUP BY t7.ID, t7.student.Name, t7.klass.Name, t7.data_ocen HAVING (((t7.data_ocen)<Date())) ORDER BY t7.student.Name;"
 
        Dim da As New OleDbDataAdapter(stSQL, Con)
        Dim dt As New DataTable
        da.Fill(dt)
 
        For Each RW In dt.Rows
            RW("Сообшение") = JoinStrOnGrp7(RW("ID"))
        Next
 
        With DataGridView1
            .DataSource = dt
            .Columns(0).HeaderText = "№ "
            .Columns(0).Width = 50
            .Columns(1).Width = 150
            .Columns(2).Width = 50
            .Columns(3).Width = 70
            .Columns(4).Width = 350
            
        End With
    End Sub
 
    Public Function JoinStrOnGrp7(on_id As Integer) As String
        Dim Con As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=1234.mdb")
        Dim dbCmd As OleDbCommand
        Dim dbRead As OleDbDataReader
        Dim stSQL, rFields As String
 
        Con.Open()
        stSQL = "SELECT [Предмет] FROM [t7] WHERE [ID]=" & on_id
        dbCmd = New OleDbCommand(stSQL, Con)
        dbRead = dbCmd.ExecuteReader()
 
        JoinStrOnGrp7 = ""
        If dbRead.HasRows Then 'проверка на наличие строк в запросе
 
            Do While dbRead.Read()
                If JoinStrOnGrp7 <> "" Then JoinStrOnGrp7 = JoinStrOnGrp7 + ","
                If dbRead.GetValue(0) Is DBNull.Value Then
                    rFields = " "
                Else
                    rFields = dbRead.GetValue(0).ToString
                End If
                JoinStrOnGrp7 = JoinStrOnGrp7 + rFields
 
            Loop
        End If
        dbRead.Close()
        dbCmd.Dispose()
        Con.Close()
    End Function

    Public Function JoinStrOnGrp7(on_id As Integer) As String
        Dim Con As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=1234.mdb")
        Dim dbCmd As OleDbCommand
        Dim dbRead As OleDbDataReader
        Dim stSQL, rFields, Name As String
        Dim p As Integer
        Dim dateF As Date
        Name = "ФИО"
 
 
        Con.Open()
        stSQL = "SELECT student.Name, data_ocen, [Предмет] FROM [t7] WHERE [ID]=" & on_id
        dbCmd = New OleDbCommand(stSQL, Con)
        dbRead = dbCmd.ExecuteReader()
 
        JoinStrOnGrp7 = ""
        If dbRead.HasRows Then 'проверка на наличие строк в запросе
 
            Do While dbRead.Read()
                If JoinStrOnGrp7 <> "" Then JoinStrOnGrp7 = JoinStrOnGrp7 + ","
                If dbRead.GetValue(2) Is DBNull.Value Then
                    rFields = " "
                Else
                    rFields = dbRead.GetValue(2).ToString
                End If
                JoinStrOnGrp7 = JoinStrOnGrp7 + rFields
                Name = dbRead.GetValue(0).ToString
                dateF = dbRead.GetValue(1)
            Loop
        End If
 
        Name = Name.Replace("  ", " ")
        p = Name.IndexOf(" ")
        If p > -1 Then
            Name = Name.Substring(0, p + 2)
        End If
        JoinStrOnGrp7 = Format(dateF, "dd.mm.yyyy") + "; " + Name + "; " + JoinStrOnGrp7
 
        dbRead.Close()
        dbCmd.Dispose()
        Con.Close()
    End Function

 JoinStrOnGrp7 = Format(dateF) + "; " + Name + "; " + JoinStrOnGrp7

stSQL = "SELECT t7.ID, t7.student.Name AS ФИО, t7.klass.Name AS Класс, t7.data_ocen AS Дата, t7.student.Name AS Сообшение FROM t7 GROUP BY t7.ID, t7.student.Name, t7.klass.Name, t7.data_ocen HAVING (((t7.data_ocen)<Date())) ORDER BY t7.student.Name;"

 stSQL = "SELECT t7.ID, t7.student.Name AS ФИО, t7.klass.Name AS Класс, t7.data_ocen AS Дата, t7.student.Name AS Сообшение FROM t7 GROUP BY t7.ID, t7.student.Name, t7.klass.Name, t7.data_ocen HAVING (((t7.data_ocen)=Date())) ORDER BY t7.student.Name;"

stSQL = "SELECT student.Name, data_ocen, [Предмет] FROM [t7] WHERE data_ocen=Date() AND [ID]=" & on_id