Nevron Open Vision Documentation
User Interface / User Input / Drag and Drop Input
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    Drag and Drop Input
    In This Topic

     

     About NDragDrop

    The NDragDrop static class manages the drag-and-drop virtual device in NOV and serves as UI event dispatcher for native drag-and-drop events, that a particular window peer receives. Following is a description of the drag-and-drop related features and services:

     Events
    Event Description Event Arguments

    Drag and Drop Action Events

    NDragDrop.DragOver Raised when the dragged data object is moved inside the current drag over target. The event is routed along the entire route from the target node to its root.  NDragActionEventArgs
    NDragDrop.DragDrop Raised when the user drops a data object inside the current drag over target. The event is routed along the entire route from the target node to its root.  NDragActionEventArgs

    Drag Over Target Events

    NDragDrop.DragEnterEvent Raised when the dragged data object enters a new drag over target. Further Drag-And-Drop Action Events will be raised for the drag over target. The event is routed along the entire route from the target node to its root.  NDragOverChangeEventArgs
    NDragDrop.DragInEvent Raised after NDragDrop.DragEnterEvent, but routed up to the last ancestor that was common between the previous drag over target and the new one. NDragOverChangeEventArgs
    NDragDrop.DragOutEvent Raised before NDragDrop.DragLeaveEvent, but routed up to the last ancestor that was common between the previous drag over target and the new one. NDragOverChangeEventArgs
    NDragDrop.DragLeaveEvent Raised when the dragged data object leaves the current drag over target. The event is routed along the entire route from the target node to its root.  NDragOverChangeEventArgs

     

     

     Extended Properties
    Property Description
    NDragDrop.DirectlyOverPropertyEx Set to true for the input target over which the drag-drop is directly over.
    NDragDrop.OverPropertyEx Set to true for the input target over which the drag-drop is directly over and all of its ancestors.
     Initiating Drag-and-Drop
    Besides dispatching Drag-and-Drop events, the NDragDrop static class can also be used to initiate drag-and-drop operations. This is achieved by calling the NDragDrop.RequestDragDrop method. See Data Exchange Overview for more information. 
     Ambient Information

    The NDragDrop also provides several methods for helping you obtain the current value of the extended properties that it has applied to a particular node. These are:

    • NDragDrop.IsDirectlyOver(NNode node) – returns the current value of the NDragDrop.DirectlyOverPropertyEx extended property for the specified node.
    • NDragDrop.IsOver (NNode node) – returns the current value of the NDragDrop.OverPropertyEx extended property for the specified node.