This repository provides code samples for displaying custom dialogs using Windows-API-Code-Pack-1.1 NuGet package, source code repository. It's not perfect as per issues below but does work well within limits.
For some creating a window form with normal buttons with DialogResult set for each button is always another way to go.
- DetailsCollapsedLabel and DetailsExpandedLabel can cause buttons to display wrong when the text is rather long.
- DetailsExpandedText has the same issue as above.
In both cases are extreme, should be fine for most cases.
The following is from the following Microsoft TeckNet article section with full source. Note working with a progressbar requires a decent understanding of the dialog.