WebDragDropExtender implemented drag-drop architecture similar to desktop application (WinForm) which significantly reduces overall learning curve. WinForm developers should be able to understand WebDragDropExtender's drag-drop events and life cycle concept, as well as the object model exposed in the drag event arguments.
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The drag-drop event argument is a client side class named ISDragEventArgs providing a set of information according to the current context of a drag-drop operation. Developers can obtain data such as the current drag's data, the allowed effects, the current mouse coordinates from the event argument. You can also give feedback to the current drag-drop event by setting the Effect and EffectText property of the event argument. |
The event argument is available in the following events:
| Event Name | Event Signature |
| OnDragEnter | (controlId, dragEventArgs, dropObject) |
| OnDragOver | (controlId, dragEventArgs, dropObject) |
| OnDragDrop | (controlId, dragEventArgs, dropObject) |
The dragEventArgs passed to the three events listed above contains drag-drop contextual information such as shown in the following table.
| Property | Description | Get | Set |
| DragObject | Represents ISDragableObject instance, which is the object being dragged by the user. | x | |
| AllowedEffects | The allowed effects specified in DragSettings.AllowedEffects of the WebDragDropExtender control. | x | x |
| Data | The data associated with a drag control. The native-string type data can be assigned directly in the DragData property of a DragControl object. | x | x |
| Effect | The default effect associated with a drag control. The effect can be set on the Effect property of a drag control or drag settings (for global appliance). | x | x |
| EffectText | The effect text (tool tip) that will be displayed when the drag control is over a valid drop target. | x | x |
| KeyState | The key state in the current context of drag operation. Key state can be combination of Ctrl, Alt, and Shift. | x | x |
| X | The X point of mouse cursor relative to the document. | x | |
| Y | The Y point of mouse cursor relative to the document. | x | |
| CursorX | The X point of mouse cursor relative to the target element. | x | |
| CursorY | The Y point of mouse cursor relative to the target element. | x | |
| IsInTargetFrame | Determines whether the drag operation is currently targeting an element inside IFRAME. | x |
To learn more about available enumerations for the Effect and KeyState, please refer to Client Side References.