arcobjects - Implement ArcGIS Custom Features with C#?

Is it possible to implement custom features in .NET?

If so, how?

I suspect the issue is being able to do COM aggregation with .NET, but I can't find anything on that ...

Does anyone know if it is possible to create a runtime COM callable wrapper for a .NET class that supports COM_INTERFACE_ENTRY_AGGREGATE_BLIND ?

Answer

You will be unable to implement pure COM aggregation in .NET 3.5 or lower, but you may be lucky in .NET 4, which adds the new ICustomQueryInterface interface, allowing you to redirect the interface queries properly. More information with a sample included can be found on codeplex.

I also recommend to proceed along the C++ ESRI docs sample. The link is for 9.0, but I suspect this particular sample has not changed one bit.