As a manager, what is the best way to deal with moody staff members? Be direct with them, or try to understand their background?

Employees tend to be, or to show being, moody when they feel desperate. When now career growth, no reward for hard-workers, no promotions, no appreciation, employees tend to be nervous and moody.

If you have the same situation and you cannot support them due to company restrictions, try to motivate them emotionally by showing appreciation for their accomplishment and consideration for their skills. but do not be too loose, other wise you will lose control.

Its better to deal with the moody staff member in a direct manner but talk to him in a calm way. As a manager, I'll make him understand that this type of attitude will cause bad relationships to other staff members and even results to no communication between them. This problem will not be tolerated by the company as it will cause to delay of work and its a bad reflection to me as a manager so I explain to him the consequences of his action. For worse cases, I will make memo to warn him as he is not helpful in the group.

try to understand their background

if i find any person moody during work , 5% of his salary will be transfered to the person who is active in work.. 

In any company, you cannot avoid to encounter such kind of employee. As a manager, it is our responsibility to know our people, their strength, weaknesses, personality and a little bit of his/her family background in able for us to easily deal with our employee/subordinates. As a manager, dealing this kind of employee, you must be open-minded and know where he/she coming coming from and try to understand them. It doesn't mean you are tolerating their behavior but instead, you are trying to understand them and make a way how to win them and translate that negative behavior into a positive one. Motivation is one key of this.

every one have a motive points even moody people , just try to standardize your style in dealing with them , sometimes you don't have to go in further details

Their assignments should be supporting rather than managing. Furhter assignments must be daily target oriented rather than long term targets because they could not be let the work at their own mood.

Further, they should be placed uner continuous couseling for letting them realized the goals of organization.