I’ve recently been tweaking the ASP.NET completion, adding support for resolving valid children for a control. These can be properties, a property, or controls. More difficult was resolving the valid children for properties, but this is now done.
Unfortunately, there aren’t actually any designer or parser attributes for limiting the children of a property, so in order to resolve the children, I assume it’s a collection, and look for an Add method with a single parameter derived from Control. If this exists, I use its parameter to filter the types in the control completion list. It’s an ugly hack, but it works perfectly for tables and wizards. In the worst case, MonoDevelop falls back to showing all controls.
With this done, the ASP.NET completion is essentially feature-complete.