I am trying to drag files from my own window into outlook and I got this ([login to view URL]).
This brilliant article demonstrates how to create a customized DataObject implementing delayed data extract on drop/paste and asynchronous data trnasfer on background thread.
It worked perfectly untill I tried to drop a file into Outlook 2016. It still works but the UI is not responsive despite the fact that my dataobject has "IsAsynchronous" set to true.
After debugging I found when dropped to Outlook [login to view URL] is not called and [login to view URL] is called on the UI thread.
My question is does Outlook support IAsyncOperation? If it does what am I missing? If it does not support IAsyncOperation, is there a workaround or different solution?