ExternalEvent in window form

[peerawit.ru]

Hi everyone 

I'm learning to create Revit add-in now i stuck in external event process.

I want to select element in Revit via window form for create dimension.

I prepare all data in window form.

How to send data back to create under transaction in external event?

[Ryan_Daley]

I also find it difficult to get a return value other than result from Revit IExternalEventHandler or IExternalCommand. 
Although I can't figure out how to return a value using only the native Revit API, I found this Revit.Async library to be useful for returning values from my Revit External Events.    

[moturi.magati.george · Accepted solution]

Hi @peerawit.ru,

You can take a look at the forum questions that might give you an insight into what you are looking for:

https://forums.autodesk.com/t5/revit-api-forum/cant-understand-how-external-event-works/td-p/9449829

https://forums.autodesk.com/t5/revit-api-forum/is-it-possible-to-obtain-objects-from-event-handlers-...

[peerawit.ru]

Thank you very much 🙏