DXDefaultEventArgs Class

Allows you to invoke or suppress actions the attached control performs on a particular drag-and-drop operation stage.

Namespace: DevExpress.Utils.DragDrop

Assembly: DevExpress.Utils.v20.1.dll

Declaration

public class DXDefaultEventArgs :
    EventArgs
Public Class DXDefaultEventArgs
    Inherits EventArgs

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.

    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;
        }
    }
    
    NOTE

    The grid provides specific methods to calculate event arguments.

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

Inheritance

See Also