How do I create a custom dialog in WiX for user input?

Have fun with UI!

Edit: The original link to answer doesn’t exist anymore. FireGiant (the maintainers of Wix) some examples for part of this process, but it’s doesn’t completely answer this question. There is one further tutorial (UPDATE Aug.2018: Link resurrected from Wayback Machine) that does go most of the way to answer this question.

A high level overview of what will be happening is:

1. Create a property
2. Have the UI control set this property
3. The name attribute on the service will reference the property, ie [ServiceNameProperty].

However this is complex, and the way that is suggested to create a new UI dialog, is to take an existing dialog, make a clone of it, and then edit with new text, controls and use it to populate the property.