Defining Drag and Drop Events in the SAP Tree

Use

This section explains the special considerations that apply to drag and drop operations in the SAP Tree.

Prerequisites

To be able to react to an event, you must first register it. Unlike normal event handling, you do not register drag and drop events with the Control Framework using the set_registered_events method. Instead, they are registered automatically by the SAP Tree control wrapper.

However, you still have to specify handler methods for the events.

The events are always registered as system events.

When you fill the node table, you must also specify which nodes are enabled for drag and drop, and the flavors that the nodes should have. You do this by assigning the relevant drag and drop behavior to the field in the node table (see point 3 under Drag and Drop Operations). This requires the following steps (see also the Drag and Drop Programming Example):

Define the drag and drop behavior:


DATA behaviour_left TYPE REF TO cl_dragdrop.
CREATE OBJECT behaviour_left.
CALL METHOD behaviour_left->add
 EXPORTING
  flavor      = 'Tree_move_to_Edit'
  dragsrc     = 'X'
  droptarget  = ' '
  effect      = cl_dragdrop=>copy.

Use the get_handle method to return a handle to the drag and drop behavior:


CALL METHOD behaviour_left->get_handle
 IMPORTING handle = handle_tree.

Assign the handle to the DRAGDROPID field of the corresponding entry in the node table:
```
node-dragdropid = handle_tree.     " handle of behaviour
```

Features

The following table contains the events used in drag and drop:

Event	Description
ON_DROP_GET_FLAVOR	See the event `ONGETFLAVOR` under Drag and Drop Events
ON_DRAG	See the event `ONDRAG` under Drag and Drop Events To be used for trees without multiple selection (`NODE_SELECTION_MODE = TREE->NODE_SEL_MODE_SINGLE`)
ON_DRAG_MULTIPLE	See the event `ONDRAG` under Drag and Drop Events For trees with multiple selection (`NODE_SELECTION_MODE = TREE->NODE_SEL_MODE_MULTIPLE`)
ON_DROP	See the event `ONDROP` under Drag and Drop Events
ON_DROP_COMPLETE	See the event `ONDROPCOMPLETE` under Drag and Drop Events To be used for trees without multiple selection (`NODE_SELECTION_MODE = TREE->NODE_SEL_MODE_SINGLE`)
ON_DROP_COMPLETE_MULTIPLE	See the event `ONDROPCOMPLETE` under Drag and Drop Events For trees with multiple selection (`NODE_SELECTION_MODE = TREE->NODE_SEL_MODE_MULTIPLE`)

The individual events have the following parameters:

Event	Event Parameter	Description
ON_DROP_GET_FLAVOR	NODE_KEY	Technical name of the node to which the source object referred
	DRAG_DROP_OBJECT	Data object for description of the source object
	FLAVORS	Common flavors of the drag-and-drop operation
ON_DRAG	NODE_KEY	Technical name of node that was selected as source object
	ITEM_NAME (not for Simple Tree)	Technical name of item that was selected as the source object
	DRAG_DROP_OBJECT	Data object for description of the source object
ON_DRAG_MULTIPLE	NODE_KEY_TABLE	Table of nodes that were selected as source objects
	ITEM_NAME (not for Simple Tree)	Technical name of item that was selected as the source object
	DRAG_DROP_OBJECT	Data object for description of the source object
ON_DROP	NODE_KEY	Technical name of the node to which the source object referred
ON_DROP	DRAG_DROP_OBJECT	Data object for description of the source object
ON_DROP_COMPLETE	NODE_KEY	Technical name of node that was selected as source object
	ITEM_NAME (not for Simple Tree)	Technical name of item that was selected as the source object
	DRAG_DROP_OBJECT	Data object for description of the source object
ON_DROP_COMPLETE_MULTIPLE	NODE_KEY_TABLE	Table of nodes that were selected as source objects
	ITEM_NAME (not for Simple Tree)	Technical name of item that was selected as the source object
	DRAG_DROP_OBJECT	Data object for description of the source object