So I was reading a bit on AutoComplete of textboxes in VB.NET, but I can't really understand where these are stored? Is it a fully built in feature, or do I have to write some code for it to work? I've found the AutoCompleteMode and AutoCompleteSource properties of textboxes. But I want to append whatever I've written in the textbox to the autocomplete source. Do I connect the source to My.Settings or something? Wouldn't I have to use an array as well? Any help would be appreciated :)
You would have to add new entries to your auto-complete data source manually... which makes sense, when you think about it: How is Windows Forms supposed to know when a new entry should be added to the list of suggestions and when the text entered is only something temporary?
You could add new values e.g. when validation of the input field happens, or when the user presses an OK / Apply button, or whatever fits your need best. But you will have to do this yourself.
The properties you've already discovered are the right ones.
Dim suggestions As New List(Of String)
suggestions.Add("Abba")
suggestions.Add("Nirvana")
suggestions.Add("Rolling Stones")
...
textBox.AutoCompleteSource = suggestions
You can bind AutoCompleteSource to almost anything; this is very similar to data-binding. One thing to keep in mind is that if you're adding new entries to the auto-complete data source, the UI control might not immediately notice if your data source doesn't implement the INotifyCollectionChanged interface.