jQuery Autocomplete: Limit number of items in the results list

Question #1

Set Top N in your query that fetches record from database where N is the maximum rows you want to fetch

Question #2

I have used dash as a separator to separate ID and Text part. So you need to change it to some other character at 2 places

customers.Add(string.Format("{0}-{1}", sdr["ContactName"], sdr["CustomerId"]));

and

response($.map(data.d, function (item) {
                            return {
                                label: item.split('-')[0],
                                val: item.split('-')[1]
                            }
                        }))