If I were you and made a reasonable profit from buying thru agents in BD I would not buy directly from China due to inherent problems. Most big Department stores in USA usually buy thru agents based in China, HK and US. These agents offer them best quality, best products, credit and stand as guarantee in case of late deliveries or bad quality. They minimise their risk .

If you buy directly from Chinese factories you will buy slightly cheaper but will have to source from different factories, ensure quality and specs , consolidate goods from different factories, pay 100% before shipment , pay freight cost and import duties, need warehouse to store goods and add distribution cost in Bangladesh. This will add cost and block your money . If goods are late or have quality problem you will lose the season and buyers.You should calculate the difference in landed price and what you buy from wholesalers in BD.

Finally the margins in electronics are very thin . If you still think it is worth the risk and effort, you can go to China or attend Canton Fair and make contact with suppliers. You can also appoint your buying agent who will buy on your behalf and safeguard your interest. There is always a risk in buying directly.

Yes you will need to follow the govt rules for importing and will need a licence moreover the foreign exchange is controlled as the currency is not fully convertible.