BeginDrag

Syntax 1: For ListView controls
Syntax 2: For TreeView controls

The BeginDrag event has different arguments for different objects:

Object	See
ListView control	Syntax 1
TreeView control	Syntax 2

Syntax 1: For ListView controls

Description

Occurs when the user presses the left mouse button in the ListView control and begins dragging.

Event ID

Event ID	Objects
pbm_lvnbegindrag	ListView

Arguments

Argument	Description
index	Integer by value (the index of the ListView item being dragged)

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 ListView'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.

Dragging a ListView item onto another control causes its standard drag events (DragDrop, DragEnter, DragLeave, and DragWithin) to occur. The standard drag events occur for ListView when another control is dragged within the borders of the ListView.

Examples

This example moves a ListView item from one ListView to another. ilvi_dragged_object is a window instance variable whose type is ListViewItem. To copy the item, omit the code that deletes it from the source ListView.

This code is in the BeginDrag event script of the source ListView:

// If the ListView's DragAuto property is FALSE
This.Drag(Begin!)
 
This.GetItem(This.SelectedIndex(), &
   ilvi_dragged_object)
 
// To copy, rather than move, omit these two lines
This.DeleteItem(This.SelectedIndex())
This.Arrange()

This code is in the DragDrop event of the target ListView:

This.AddItem(ilvi_dragged_object)
This.Arrange()

See also

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 dragged)

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:

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:

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.