userform comboboxes to automatically update as new entries are put into column.

Hi there,

I have 5 different combo boxes within a userform interface. Each combobox corresponds to a different column. I have labelled the combo box as 'cbo' followed by their column name:

cboDocumentSort = column B
cboDocumentRef = column C
cboRelatedRef = column D
cboEngineType = column K
cboUnitType = column L


I want these comboboxes within my userform to display the data I have in these columns accordingly:

1) Some of the data repeats in the columns, so I do not want it to show the same text twice in the combobox.
2) I would like it to show alphabetically.
3) If completely new data is inserted into these columns, that the combobox will automatically update its list with the additional values in the columns.


Thank you.

My question is what is the vba coding to do this?

Would the vba coding be in Userform_Initialize sub?