MATLAB: Pass information from Listbox to textbox

edit textboxlistbox

I want to select multiple elements from from a listbox and display those elements in the edit textbox side by side. For example if I select 'A' from the listbox, 'A' should be displayed in the edit textbox. And then if I click 'B' from the listbox, 'B' should be displayed on the edit textbox next 'A'. Therefore the edit textbox should look like 'AB'.
How do I do this?