问题
I have successfully populated a TreeView via creating a TreeDataProvider and customized the icons and its collapse-able property. Now I want to be able to drag and drop its ViewItem(s) onto a WebView. There are unfortunately no samples for drag and drop. Reading through the TreeView source, ViewItem(s) are created in HeightMap.OnInsertItems() via the TreeView.createViewItem(), from the derived class.
The public TreeView.onInsertItem() would appear to be a great extension point, extending TreeView and onInsertItem() and capturing its ViewItem parameter. This Unfortunately, the creation of the concrete class, ExtHostTreeView, that is ultimately created, is buried in layers of private methods (createExtHostTreeViewer()).
Strangely, the ViewItem has a setter for draggable. However, how would you ever get a reference to the ViewItem to set it? If there is a way to do this please point me at an example. If there is not, I would be glad to fork and implement it. Leaving the existing onInsertItem and perhaps add an array of handlers to be added to with an addOnInsertItemListener() method? Or perhaps use RxJS?
There are so many places this could be used. You could drag template fragments into documents or code, DSL rules into a expert system, configuration file values into parameters or right hand values (generating the code to retrieve the value). Thank you for any assistance.
回答1:
It seems that drag and drop in custom views is currently not supported. There's a (fairly popular) feature request for it here:
Add drag and drop for contributed tree views (#32592)
来源：https://stackoverflow.com/questions/51716794/adding-drag-and-drop-support-in-a-custom-treeview