Class DragAndDrop

The DragAndDrop class provides a way to manage drag and drop operations in App UI.

Inheritance
object
DragAndDrop
Inherited Members
Namespace: Unity.AppUI.Core
Assembly: Unity.AppUI.dll
Syntax
public static class DragAndDrop
Remarks

You can use this class to handle drag and drop at Runtime or in the Editor.

Examples
using Unity.AppUI.Core;

// be sure to call this method during a PointerDown or PointerMove event to work properly.
public void StartDraggingItems()
{
   var draggedItems = GetItemsToDrag();
   DragAndDrop.PrepareStartDrag();
   DragAndDrop.objects = draggedItems;
   DragAndDrop.StartDrag($"{draggedItems.Count} list item{(draggedItems.Count > 1 ? "s" : "")}");
}

If you want to handle dropping items, you can use the DropZone UI element, or the DropZoneController controller for a lower-level approach. 

using Unity.AppUI.Core;
using Unity.AppUI.UI;

public class MyMainView : VisualElement
{
public MyMainView()
{
var dropZone = new DropZone();
dropZone.controller.acceptDrag = ShouldAcceptDrag;
dropZone.controller.dropped += OnDropped;
dropZone.controller.dragEnded += CleanUp;
Add(dropZone);
}


bool ShouldAcceptDrag(IEnumerable<object> draggedObjects)
{
    // return true or false depending on if the drop zone should accept the dragged objects
}

void OnDropped(IEnumerable<object> droppedItems)
{
    // handle the dropped items here...
    CleanUp();
}

void CleanUp()
{
    // clean up any state set up when the drag operation started
}



}

Properties

activeDropTarget

The active drop target.

Declaration
public static Manipulator activeDropTarget { get; }
Property Value
Type Description
Manipulator

count

The number of objects being dragged.

Declaration
public static int count { get; }
Property Value
Type Description
int

objects

The objects being dragged.

Declaration
public static IEnumerable<object> objects { get; set; }
Property Value
Type Description
IEnumerable<object>

state

The current state of the drag and drop operation.

Declaration
public static DragAndDropState state { get; set; }
Property Value
Type Description
DragAndDropState

Methods

Drop()

Drops the dragged objects.

Declaration
public static IEnumerable<object> Drop()
Returns
Type Description
IEnumerable<object>

The dropped objects.
Remarks

This is the equivalent of AcceptDrag.

PrepareStartDrag()

Clears drag and drop data.

Declaration
public static void PrepareStartDrag()

StartDrag(string)

Start a drag operation.

Declaration
public static void StartDrag(string title)
Parameters
Type Name Description
string title

The title of the drag operation.
Remarks

This method must be called after setting the dragged objects, and during a PointerDown or PointerMove event.