get data to combobox vb.net

  Imports System.Data.OleDb
        Dim strSQL As New String
        Dim cmd As OledbCommand
        Dim Dr As OleDbDataReader
        connection.Open()
        strSQL = "select Myfield from MyTables"
        cmd = New OleDbCommand
        cmd.CommandText = strSQL
        cmd.Connection = connectionDB
        Dr = cmd.ExecuteReader
        While (Dr.Read())
            Combobox1.Items.Add(Dr("Myfield"))
        End While
        cmd.Dispose()
        Connection.Close()