how to update combobox with items from DB

Question

Hi all.
I've been searching for this for some time but still i'm not able to update my comboboxes. The scenarios is as following: i have a combobox with items from a sql database. I have an add and remove button for adding and removing values from the database table where that combobox is receiving the values. The thing is when i add or remove, it adds or removes from the database but the combobox will not reproduce those changes in runtime. How can i do that? I've tryied to inicialize the combobox all over again the same way it does when the application first starts but all i get is or an empty combobox or the items remain the same.

I really would like some help in this matter.

Thank you all!!