What are things/points to keep in mind while developing a reusable custom control?

Windows Form (in C#) - I need to create a custom listbox control for the following requirement:

There is a listbox with a long list of items. I want the user to be able to click in the list, and then start typing and have it automatically take them to the matching item (I call this "type ahead"). It needs to be able to do this for as many characters as they type that have a match.

This con开发者_如何学JAVAtrol should be really reusable without much changes.

What are things/points I should keep in mind while developing a reusable custom control? (if you provide a good pattern as a sample... will be more helpful)

In Real World scenario the first decision should be buy vs build. if your application is a serious one and not just for hobby and there is budget for it I would check some of those great controls collections like DevExpress or Telerik for WinForms. You would need a grid as well at some point, eventually, and surely your custom or framework one cannot compete theirs.

I refer to those libraries because i believe they already have a listbox with autocomplete as you described in your requirements. check the online demos on their websites...