DragDropBehaviorBase<TDragDropBehaviorSource, TDragDropBehaviorProperties>.DragEnter Event

Occurs when a data element is dragged into the control’s bounds.

Namespace: DevExpress.Utils.DragDrop

Assembly: DevExpress.Utils.v24.1.dll

NuGet Packages: DevExpress.Utils, DevExpress.Wpf.Core

Declaration

C#

[DXCategory("DragDrop")]
public event DragEnterEventHandler DragEnter

VB.NET

<DXCategory("DragDrop")>
Public Event DragEnter As DragEnterEventHandler

Event Data

The DragEnter event's data class is DragEnterEventArgs. The following properties provide information specific to this event:

Property	Description
Action	Gets or sets the drag-and-drop action (Copy, Move, etc.) to perform. Inherited from DXDragEventArgs.
AllowDrop	Gets or sets whether it is allowed to drop data elements to the target control.
Cursor	Gets or sets the mouse pointer. Inherited from DXDragEventArgs.
Data	Gets or sets the data elements being dragged. Inherited from DXDragEventArgs.
Handled	Gets or sets whether the event was handled and allows you to suppress the default action. Inherited from DXDefaultEventArgs.
KeyState	Gets the pressed mouse buttons (left, middle, right) and modifier keys (Shift, Ctrl, Alt). Inherited from DXDragEventArgs.
Location	Gets the mouse cursor’s position. Inherited from DXDragEventArgs.
Source	Gets the source control. Inherited from DXDragEventArgs.
Target	Gets the target control. Inherited from DXDragEventArgs.

The event data class exposes the following methods:

Method	Description
Default()	Invokes the default action the attached control performs on the current drag-and-drop operation stage. Inherited from DXDefaultEventArgs.
GetData<T>()	Returns the data elements being dragged. Inherited from DXDragEventArgs.

Remarks

If you attached the Drag-and-Drop Behavior to a control in the designer, use the DragDropEvents component to subscribe to the drag-and-drop events.

Example

This example shows how to prohibit to drop specific data.

C#

private void dragDropEvents1_DragEnter(object sender, DragEnterEventArgs e) {
    List<TreeListNode> list = e.Data as List<TreeListNode>;
    // You can prohibit to drop specific data.
    if (list.Find((x) => x.GetValue(colDEPARTMENT1).ToString().Contains("Finance")) != null) {
        e.AllowDrop = false;
        e.Cursor = Cursors.No;
        e.Handled = true;
    }
}

private void dragDropEvents1_DragOver(object sender, DevExpress.Utils.DragDrop.DragOverEventArgs e) {
    List<TreeListNode> list = e.Data as List<TreeListNode>;
    // You can prohibit to drop specific data.
    if (list.Find((x) => x.GetValue(colDEPARTMENT1).ToString().Contains("Finance")) != null) {
        e.Cursor = Cursors.No;
        e.Handled = true;
    }
}

VB.NET

Private Sub dragDropEvents1_DragEnter(ByVal sender As Object, ByVal e As DevExpress.Utils.DragDrop.DragEnterEventArgs) _
    Handles dragDropEvents1.DragEnter
    Dim list As List(Of TreeListNode) = TryCast(e.Data, List(Of TreeListNode))
    ' You can prohibit to drop specific data.
    If list.Find(Function(x) x.GetValue(colDEPARTMENT1).ToString().Contains("Finance")) IsNot Nothing Then
        e.AllowDrop = false
        e.Cursor = Cursors.No
        e.Handled = True
    End If
End Sub

Private Sub dragDropEvents1_DragOver(ByVal sender As Object, ByVal e As DevExpress.Utils.DragDrop.DragOverEventArgs) _
    Handles dragDropEvents1.DragOver
    Dim list As List(Of TreeListNode) = TryCast(e.Data, List(Of TreeListNode))
    ' You can prohibit to drop specific data.
    If list.Find(Function(x) x.GetValue(colDEPARTMENT1).ToString().Contains("Finance")) IsNot Nothing Then
        e.Cursor = Cursors.No
        e.Handled = True
    End If
End Sub

Note

Run the XtraTreeList or XtraGrid demo and click Open Solution for more examples.