OLEStartDrag Event, SftButton Object
Source object is starting an OLE drag & drop operation.
Syntax
| VB.NET | Private Sub object_OLEStartDrag(ByVal sender As Object, ByVal e As EventArgumentType) Handles object.OLEStartDrag |
| VB | Private Sub object_OLEStartDrag(Data As DataObject, AllowedEffects As Long) |
| C#.NET | void object_OLEStartDrag(object sender, EventArgumentType e); |
| VC++ | void OnOLEStartDragobject(struct IVDMDataObject** Data, long* AllowedEffects); |
| C | HRESULT OnOLEStartDragobject(struct IVDMDataObject** Data, long* AllowedEffects); |
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 and you should provide the values for the Data parameter.
AllowedEffects
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.
Comments
The OLEStartDrag event occurs when source object is starting an OLE drag & drop operation.
This event specifies the data formats and drop effects that the source component supports. It can also be used to insert data into the DataObject object.
You may want to defer placing data into the DataObject object until the target component requests it. This allows the source component to save time by not loading multiple data formats. When the target performs the GetData method on the DataObject, the source's OLESetData event will occur if the requested data is not contained in the DataObject. At this point, the data can be loaded into the DataObject, which will in turn provide the data to the target.
If the user does not load any formats into the DataObject using SetData, the drag & drop operation is cancelled.
AllowedEffects must be set to vbDropEffectCopy or vbDropEffectMove, otherwise the drag & drop operation is cancelled.
See Also SftButton Object | Object Hierarchy
On
Off