Ottento il seguente errore quando provo a impostare un datagridview

vi posto sotto il codice

codice:
 Private Sub frmEditUser_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim query = "SELECT * FROM utente"
        Dim strCon = cn.ConnectionString
        rs.let_ActiveConnection(strCon)
        If (rs.State = 1) Then
            rs.Close()
        Else
            rs.let_Source(query)
            rs.Open()
        End If
        Dim id_grp As Integer() = New Integer(100) {}
        Dim grp_testo As String() = New String(100) {}
        Dim x As Integer
        Do Until rs.EOF
            id_grp(x) = rs.Fields.Item(0).Value.ToString
            grp_testo(x) = rs.Fields.Item(1).Value.ToString
            rs.MoveNext()
            x = x + 1
        Loop
        Dim numRighe As Integer = id_grp.Count.ToString

       

        DataGridView1.ColumnHeadersVisible = True
        Dim columnHeaderStyle As New DataGridViewCellStyle()
        columnHeaderStyle.BackColor = Color.Beige
        columnHeaderStyle.Font = New Font("Verdana", 10, FontStyle.Bold)
        DataGridView1.ColumnHeadersDefaultCellStyle = columnHeaderStyle
        ' Set the column header names.
        Dim cell1 As DataGridViewCell = New DataGridViewTextBoxCell()
        Dim col1 = New DataGridViewColumn()
        With col1
            .Name = "ID"
            .HeaderText = "ID"
            .CellTemplate = cell1
            .DataPropertyName = "ID"
        End With
        Dim col2 = New DataGridViewColumn()
        With col2
            .Name = "COGNOME"
            .HeaderText = "COGNOME"
            .DataPropertyName = "COGNOME"
        End With
        Dim col3 = New DataGridViewColumn()
        With col3
            .Name = "NOME"
            .HeaderText = "NOME"
            .DataPropertyName = "NOME"
        End With
        Dim col4 = New DataGridViewComboBoxColumn()
        With col4
            .Name = "ATTIVO"
            .HeaderText = "ATTIVO"
            .DataPropertyName = "ATTIVO"
        End With
        Dim col5 = New DataGridViewColumn()
        With col5
            .Name = "GRUPPO"
            .HeaderText = "GRUPPO"
            .DataPropertyName = "GRUPPO"
        End With

        Me.DataGridView1.Columns.AddRange(col1, col2, col3, col4, col5)




        Dim query2 = "SELECT * FROM utente"
        rs2.let_ActiveConnection(strCon)
        If (rs2.State = 1) Then
            rs2.Close()
        Else
            rs2.let_Source(query)
            rs2.Open()
        End If

        Do Until rs2.EOF

            Dim c1 As String = rs2.Fields(0).Value.ToString
            Dim c2 As String = rs2.Fields(1).Value.ToString
            Dim c3 As String = rs2.Fields(2).Value.ToString
            Dim c4 As String = rs2.Fields(4).Value.ToString
            Dim c5 As String = rs2.Fields(3).Value.ToString
            Dim rigaNuova() As String = {c1, c2, c3, c4, c5}
            Me.DataGridView1.Rows.Add(rigaNuova)

            'Me.DataGridView1.Item(3, numRiga).Value = rs2.Fields(3).Value.ToString
            'Me.DataGridView1.Item(4, numRiga).Value = rs2.Fields(4).Value.ToString
            rs2.MoveNext()
        Loop
    End Sub
da quanto capisco si tratta di dirgli di che tipo sono i dati. ma come la imposto la proprietà?