Cargar combobox en datagrid

Public Sub tipo_dato()
        For i As Integer = 0 To dg_variables.Rows.Count - 1 ' filas
            Dim dg_cb As New DataGridViewComboBoxCell
            dg_cb.Items.Add("Hola1")
            dg_cb.Items.Add("Hola2")
            dg_cb.Items.Add("Hola3")
            dg_variables.Item(col_tipo, i) = dg_cb
        Next
    End Sub

Agregar filas DataGridView

Dim datos As List(Of String)
DataGridView1.Rows.Add("CPCS", "", "R", "", "", "0", "", "0", "", "0")
DataGridView1.Rows.Add(datos(0), datos(1), datos(2),datos(3),datos(4), datos(5), datos(6), datos(7), datos(8))