How to Drag files from OS with realtime feedback?

[kevin--]

I have a Win32 based application using WebView2. We want to allow the user to drag some files from their desktop. There are different hit areas for what will happen based on their drag (e.g on the left side, we import immediately, on the right side, we add to a list)

Of course with add_NewWindowRequested we get a notification when the drop has completed, but there is no x, y data associated. This is also very sub par since there is no realtime feedback.

Using the ICoreWebView2CompositionController3 I see we can orchestrate the drag & drop events ourselves, however I cannot get the composition controller to draw any web content. I do not see how to use Win32 and put_RootVisualTarget successfully together. What am I missing here? What are my options?

Also concerning to see all of the other bug reports in web runtime behavior that the composition controller has filed against it...

[castorix]

I mainly tested in WinUI 3/C# and WebView2 COM interfaces, but I've been helped by MS samples from https://github.com/MicrosoftEdge/WebView2Samples/tree/main/SampleApps
(WebView2APISample and WebView2SampleWinComp)
For Drag&Drop from outside application, I implemented IDropTarget and IDropTargetHelper interfaces with ICoreWebView2CompositionController3.DragEnter and so on :