DragDrop.DragEnter Attached Event
Occurs when an object is dragged into the bounds of an element that is acting as a drop target.
Assembly: PresentationCore (in PresentationCore.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation
This event is raised once each time an object is dragged into the bounds of an element that is acting as a drop target. This event is not raised if the element’s AllowDrop property is false.
Handling this event is optional for the drop target, and is not necessary for all drag-and-drop scenarios. You typically handle this event to provide a preview of the effects of the drag-and-drop operation, if appropriate for your application. Do not set the DragEventArgs.Effects property in the event, as it will be overwritten in the DragOver event.
Routed Event Information
The following example shows the event handler for an Ellipse element. This code previews the effects of the drag-and-drop operation by saving the current Fill brush. It then checks to see if the DataObject being dragged over the ellipse contains string data that can be converted to a Brush. If so, the Brush is applied to the ellipse. The change is reverted in the DragLeave event handler. If the data cannot be converted to a Brush, no action is performed.
Private _previousFill As Brush = Nothing Private Sub Ellipse_DragEnter(ByVal sender As System.Object, ByVal e As System.Windows.DragEventArgs) Dim ellipse = TryCast(sender, Ellipse) If ellipse IsNot Nothing Then ' Save the current Fill brush so that you can revert back to this value in DragLeave. _previousFill = ellipse.Fill ' If the DataObject contains string data, extract it. If e.Data.GetDataPresent(DataFormats.StringFormat) Then Dim dataString = e.Data.GetData(DataFormats.StringFormat) ' If the string can be converted into a Brush, convert it. Dim converter As New BrushConverter() If converter.IsValid(dataString) Then Dim newFill As Brush = CType(converter.ConvertFromString(dataString), Brush) ellipse.Fill = newFill End If End If End If End Sub
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)