Enable Typing & adding new item to datagridcomboboxcolumn at runtime

See more:

.NET

Dear sir

now i have a form with datagridview which has inside it datagridcomboboxcolumn binded to mysql DB table , now i want to be able to add a new item to this combobox in runtime

after many thinking & searching , there is two ways for that and all having problems to be done

1st : the best pretty method
enabling typing in the combobox and if these word not in the list call function for ex: AddToDB(string Newitem) then refresh the combobox
problems: 1st problem enabling types there is a code in many sites (enable dropdown style and then compare the new item and if it is new add it ) but it didn't work well sometime i readd an already exist items , 2nd problem i failed failed failed to refresh/ update the items in the combobox

2nd : less pretty method
to add to the end of the list a word NEW or Add for example and handle endedit event and then pop an input box to enter the new item and then call function for ex: AddToDB(string Newitem)then refresh the combobox datagridcomboboxcolumn items

thanks all bye

the problem : 2nd problem i failed failed failed to refresh/ update the items in the combobox

so i need all your help and tips , i wish to be able to make the 1st method and if not then the 2nd one and in all cases i want to know how to refresh