DragOverEvent

Remarks

This is the half an OS drag-in cannot have and an in-app drag is mostly made of. The useful part of a drag is not the drop, it is the feedback on the way — a row that opens a gap where the thing would land, a slot that lights up, a cursor that says copy rather than move. All of that needs the payload before the button comes up, which is what Data here is for.

⚠ Addressed to one element and it is not the hit-test result. It goes to the nearest ancestor of what is under the pointer that has AllowDrop set, because Entered and Left have to be a matched pair — raised on every leaf the pointer crossed they would arrive dozens of times while the pointer travelled across one row of text, and a target that opened a gap on enter would flicker it. It bubbles from there like everything else.

Fields and properties (7)

• public DragOverStage Stage

  Coming on, moving over, or going away.

• public float X

  Where the pointer is, in the surface's space.

• public float Y

  Ditto.

• public DataObject Data

  What would be dropped.

• public UiElement? DragSource

  The element the drag started on.

• public DropEffect Allowed

  Everything the source is willing to have happen.

• public DropEffect Effect

  What this target would do, which it may narrow or refuse.

Used by (7)

• BuildContextVixen.Ui
• CompositionTestsVixen.Ui.Tests
• DropSheetVixen.Ui.Controls.Tests
• DroppedVixen.Ui.Tests
• InAppDragTestsVixen.Ui.Tests
• KeyboardDragTestsVixen.Ui.Tests
• UiDocumentVixen.Ui