DXDefaultEventArgs.Handled Property

Gets or sets whether the event was handled and allows you to suppress the default action.

Namespace: DevExpress.Utils.DragDrop

Assembly: DevExpress.Utils.v23.2.dll

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

Declaration

C#

public bool Handled { get; set; }

VB.NET

Public Property Handled As Boolean

Property Value

Type	Description
Boolean	true to suppress the default action; otherwise, false.

Remarks

Controls that support the Drag-and-Drop Behavior have a default action for each stage of a drag-and-drop operation. For instance, when data elements are dragged over a control, the control calculates the insert indicator’s bounds. When data elements are dropped, the control moves or copies data elements. The following arguments allow you to invoke or suppress the default action:

• The Handled property - gets or sets whether you handled the event. If the event is handled, the control does not perform the default action.

• The Default() method - invokes the default action. If you call this method, the Handled property is automatically set to true.

  If you want to implement your own action on a particular operation stage, set the Handled property to true to disable the default action. Use the Default() method to calculate event arguments and then change the action. In the example below, users can only insert data items as child nodes.

  C#

  dragDropEvents1.DragOver += DragDropEvents1_DragOver;
  //The code below only allows users to insert data as child nodes in a tree list.
  private void DragDropEvents1_DragOver(object sender, DevExpress.Utils.DragDrop.DragOverEventArgs e) {
      e.Default();
      if (e.InsertType != DevExpress.Utils.DragDrop.InsertType.AsChild){
          e.Action = DevExpress.Utils.DragDrop.DragDropActions.None;
          e.InsertType = DevExpress.Utils.DragDrop.InsertType.None;
      } else {
          e.Action = DevExpress.Utils.DragDrop.DragDropActions.All;
      }
  }
  

  VB.NET

  'The code below only allows users to insert data as child nodes in a tree list.
  Private Sub DragDropEvents1_DragDrop(sender As Object, e As DragDropEventArgs) Handles DragDropEvents1.DragDrop
      e.Default()
      If e.InsertType <> DevExpress.Utils.DragDrop.InsertType.AsChild Then
          e.Action = DevExpress.Utils.DragDrop.DragDropActions.None
          e.InsertType = DevExpress.Utils.DragDrop.InsertType.None
      Else
          e.Action = DevExpress.Utils.DragDrop.DragDropActions.All
      End If
  End Sub
  

  Note

  The grid provides specific methods to calculate event arguments.

  • For the DragOver event - the static (Shared in VB) GetDragOverGridEventArgs(DragOverEventArgs) method.
  • For the DragDrop event - the static (Shared in VB) GetDragDropGridEventArgs(DragDropEventArgs) method.

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the Handled property.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

drag-drop-grid-rows-to-treelist/CS/DragAndDropRows/Form1.cs#L113

e.Action = DragDropActions.Copy;
e.Handled = true;
e.Cursor = Cursors.Default;

VB.NET

drag-drop-grid-rows-to-treelist/VB/DragAndDropRows/Form1.vb#L108

e.Action = DragDropActions.Copy
e.Handled = True
e.Cursor = Cursors.Default