SftButton.OLEDragOver Event	Softel vdm, Inc.

An object is dragged over the control.

Syntax       

		VB.NET	Private Sub object_OLEDragOver(ByVal sender As Object, ByVal e As EventArgumentType) Handles object.OLEDragOver
		VB	Private Sub object_OLEDragOver(Data As DataObject, Effect As Long, Button As Integer, Shift As Integer, x As Single, y As Single, State As SftButtonOLEDragOverConstants)
		C#.NET	void object_OLEDragOver(object sender, EventArgumentType e);
		VC++	void OnOLEDragOverobject(struct IVDMDataObject** Data, long* Effect, short* Button, short* Shift, float* x, float* y, enum SftButtonOLEDragOverConstants* State);
		C	HRESULT OnOLEDragOverobject(struct IVDMDataObject** Data, long* Effect, short* Button, short* Shift, float* x, float* y, enum SftButtonOLEDragOverConstants* State);
		Delphi	procedure objectOLEDragOver(Sender: TObject; var Data : IVDMDataObject; var Effect : Integer; var Button : Smallint; var Shift : Smallint; var x : Single; var y : Single; var State : TOleEnum);

object

A SftButton object.

Data

A DataObject object containing formats that the source will provide and, in addition, possibly the data for those formats. If no data is contained in the DataObject, it is provided when the control calls the GetData method. The SetData and Clear methods cannot be used here.

Effect

A Long variable set by the source object identifying all effects it supports. This parameter must be correctly set by the target component during this event. The value of Effect is determined by logically Or'ing together all active effects. The target component should check these effects and other parameters to determine which actions are appropriate for it, and then set this parameter to one of the allowable effects (as specified by the source) to specify which actions will be performed if the user drops the selection on the component.

Name	Value	Description
vbDropEffectNone	0	Drop target cannot accept the data.
vbDropEffectCopy	1	Drop results in a copy of data from the source to the target. The original data is unaltered by the drag operation.
vbDropEffectMove	2	Drop results in data being moved from the drag source to the drop source. The drag source should remove the data from itself after the move.

Note: Only Visual Basic offers the predefined constants vbDropEffectNone, etc. When using other languages, the constants have to be defined explicitly by the application.

Button

Describes the button(s) that are pressed. The Button argument is a bit field with bits corresponding to the left button, right button and middle button. These bits correspond to the values shown below. The bits set indicate the button that caused the event.

Name	Value	Description
constSftButtonLeftButton	1	Left button
constSftButtonRightButton	2	Right button
constSftButtonMiddleButton	4	Middle button

Shift

Describes the state of the SHIFT, CONTROL and ALT keys. A bit is set if the key is down. The Shift argument is a bit field with bits corresponding to the SHIFT, CONTROL and ALT keys. It indicates the state of these keys. Some, all, or none of the bits can be set, indicating which of the keys are pressed.

Name	Value	Description
constSftButtonShiftMask	1	Shift
constSftButtonCtrlMask	2	Control
constSftButtonAltMask	4	Alt

x

The x coordinate of the mouse cursor. The units used depend on the container (Visual Basic uses TWIPS, Visual C++ uses pixels, etc.) and the coordinate system used.

y

The y coordinate of the mouse cursor. The units used depend on the container (Visual Basic uses TWIPS, Visual C++ uses pixels, etc.) and the coordinate system used.

State

Defines the transition state of the data being dragged in relation to the target control.

Name	Value	Description
enterSftButton	0	Source component is being dragged within the range of a target.
leaveSftButton	1	Source component is being dragged out of the range of a target.
overSftButton	2	Source component has moved from one position in the target to another.

Comments

The OLEDragOver event occurs when an object is dragged over the control.

The OLEDragOver event only occurs if the OLEDropMode property is set to OLEDropSftButtonManual.

The source control should always mask values from the Effect parameter to insure compatibility with future implementations of OLE drag & drop. Presently, only three bits in the Effect parameter are used. In future versions other bits may be used. As a precaution against future problems, drag sources and drop targets should mask these values appropriately before performing any comparisons.

For example, a source component should not compare an Effect against, for example, vbDropEffectCopy, such as:

  If Effect = vbDropEffectCopy...

Instead, the source component should mask the value or values being sought, as here:

  If (Effect And vbDropEffectCopy) = vbDropEffectCopy...

-or-

  If (Effect And vbDropEffectCopy)...

This allows for the definition of new drop effects in future versions while preserving compatibility with existing code.