Syntax 2: For TreeView controls
Description
Occurs when the user presses the left mouse button on a label in
the TreeView control and begins dragging.
Event ID
|
Event ID |
Objects |
|---|---|
|
pbm_tvnbegindrag |
TreeView |
Arguments
|
Argument |
Description |
|---|---|
|
handle |
Long by value (handle of the TreeView item being |
Return Values
Long.
Return code choices (specify in a RETURN statement):
0 — Continue processing
Usage
BeginDrag and BeginRightDrag events occur when the user presses
the mouse button and drags, whether or not dragging is enabled. To
enable dragging, you can:
-
Set the DragAuto property to true. If the TreeView’s DragAuto
property is true, a drag operation begins automatically when the
user clicks. -
Call the Drag function. If DragAuto is false, then in the
BeginDrag event script, the programmer can call the Drag function to
begin the drag operation.
The user cannot drag a highlighted item.
Dragging a TreeView item onto another control causes the control’s
standard drag events (DragDrop, DragEnter, DragLeave, and DragWithin) to
occur. The standard drag events occur for TreeView when another control
is dragged within the borders of the TreeView.
Examples
This example moves the first TreeView item in the source TreeView
to another TreeView when the user drags there. itvi_dragged_object is a
window instance variable whose type is TreeViewItem. To copy the item,
omit the code that deletes it from the source TreeView.
This code is in the BeginDrag event script of the source
TreeView:
|
1 2 3 4 5 6 7 8 9 10 |
long itemnum // If the TreeView's DragAuto property is FALSE This.Drag(Begin!) itemnum = 1 This.GetItem(itemnum, itvi_dragged_object) // To copy, rather than move, omit these two lines This.DeleteItem(itemnum) This.SetRedraw(TRUE) |
This code is in the DragDrop event of the target TreeView:
|
1 2 |
This.InsertItemLast(0, itvi_dragged_object) This.SetRedraw(TRUE) |
Instead of deleting the item from the source TreeView immediately,
consider deleting it after the insertion in the DragDrop event
succeeds.
See also