Assign a string to the item in listbox

Question

Hi
i am new to c# program and have a problem in dealing with my listbox item. I hope you all can help.

i have a listbox and each item entered wil automatic been assign a string. This string is editable when user click on the edit button(a form will be appear for user to edit). Ok, now my problem is how can i allow the string to assign to the item and how to store back the string (if it had been edited) to the item again.

I am sorry if this question is simple to u all but please help and guide me along, thank u