Hello,
You should have a look at the "AutoComplete" properties of the text box.
There is:
AutoCompleteSource
that let's you set the source for autocompletion (File System, last URL, browser history, custom, ...)
AutoCompleteMode
that let's you select the way suggestions are proposed to the user
AutoCompleteCustomSource
that let's you set the list of suggestion (it is a string collection) when the
AutoCompleteSource is set to
CustomSource.
I hope those properties will help you solve your problem.