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DragDropEffects Enumeration

Specifies the possible effects of a drag-and-drop operation.

This enumeration has a FlagsAttribute attribute that allows a bitwise combination of its member values.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

'Declaration
<FlagsAttribute> _
Public Enumeration DragDropEffects

Member nameDescription
NoneThe drop target does not accept the data.
CopyThe data from the drag source is copied to the drop target.
MoveThe data from the drag source is moved to the drop target.
LinkThe data from the drag source is linked to the drop target.
ScrollThe target can be scrolled while dragging to locate a drop position that is not currently visible in the target.
AllThe combination of the Copy, Move, and Scroll effects.

This enumeration is used by the following classes: DragEventArgs, GiveFeedbackEventArgs, and Control.

You can use DragDropEffects to display different mouse pointers for drag-and-drop operations. For example, you can display a plus symbol for a Copy drag-and-drop operation, an arrow symbol for a Move drag-and-drop operation, or a red circle with a line through it symbol for a None drag-and-drop operation.

If you want to drop data at a position in the target that is not currently visible, you could scroll the target while dragging. If a target does not support scrolling, you must make sure that the drop position is visible in the target before you begin the drag-and-drop operation. The following are some scenarios when you might want to scroll a target:

  • You are dragging text into a document, and you want to drop the text at a position not visible in the document window.

  • You are dragging a file into a file tree, and you want to drop the file on a node not visible in the file tree.

This code example demonstrates using the DragDropEffects enumeration when the user moves the mouse over the drop target during a drag-and-drop operation. This code example is part of a larger example provided for the DoDragDrop method of the Control class. See the DoDragDrop method for the complete code example.


Private Sub ListDragTarget_DragOver(ByVal sender As Object, ByVal e As DragEventArgs) Handles ListDragTarget.DragOver
    ' Determine whether string data exists in the drop data. If not, then
    ' the drop effect reflects that the drop cannot occur.
    If Not (e.Data.GetDataPresent(GetType(System.String))) Then

        e.Effect = DragDropEffects.None
        DropLocationLabel.Text = "None - no string data."
        Return
    End If

    ' Set the effect based upon the KeyState.
    If ((e.KeyState And (8 + 32)) = (8 + 32) And _
        (e.AllowedEffect And DragDropEffects.Link) = DragDropEffects.Link) Then
        ' KeyState 8 + 32 = CTL + ALT

        ' Link drag-and-drop effect.
        e.Effect = DragDropEffects.Link

    ElseIf ((e.KeyState And 32) = 32 And _
        (e.AllowedEffect And DragDropEffects.Link) = DragDropEffects.Link) Then

        ' ALT KeyState for link.
        e.Effect = DragDropEffects.Link

    ElseIf ((e.KeyState And 4) = 4 And _
        (e.AllowedEffect And DragDropEffects.Move) = DragDropEffects.Move) Then

        ' SHIFT KeyState for move.
        e.Effect = DragDropEffects.Move

    ElseIf ((e.KeyState And 8) = 8 And _
        (e.AllowedEffect And DragDropEffects.Copy) = DragDropEffects.Copy) Then

        ' CTL KeyState for copy.
        e.Effect = DragDropEffects.Copy

    ElseIf ((e.AllowedEffect And DragDropEffects.Move) = DragDropEffects.Move) Then

        ' By default, the drop action should be move, if allowed.
        e.Effect = DragDropEffects.Move

    Else
        e.Effect = DragDropEffects.None
    End If

    ' Gets the index of the item the mouse is below. 

    ' The mouse locations are relative to the screen, so they must be 
    ' converted to client coordinates.

    indexOfItemUnderMouseToDrop = _
        ListDragTarget.IndexFromPoint(ListDragTarget.PointToClient(New Point(e.X, e.Y)))

    ' Updates the label text.
    If (indexOfItemUnderMouseToDrop <> ListBox.NoMatches) Then

        DropLocationLabel.Text = "Drops before item #" & (indexOfItemUnderMouseToDrop + 1)
    Else
        DropLocationLabel.Text = "Drops at the end."
    End If

End Sub


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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