RadGridViewDragDropService
RadGridView handles the whole drag and drop operation by its RadGridViewDragDropService. It exposes the following public properties:
GridViewElement: Gets the RadGridViewElement.
Behavior: Gets the respective IGridDragDropBehavior according to the drop target. It is used for preparing the drag hint. The available behaviors are:
| Target Element | GridDragDropBehavior |
|---|---|
| GridHeaderCellElement | GridColumnDragDropBehvavior |
| GridDataRowElement | GridRowDragDropBehavior |
AllowAutoScrollRowsWhileDragging: Gets or set a value indicating whether rows scrolling is enabled while dragging.
AllowAutoScrollColumnsWhileDragging: Gets or set a value indicating whether columns scrolling is enabled while dragging.
Drag and Drop in Unbound Mode
By default, RadGridView supports rows drag and drop functionality in unbound mode out of the box. It is necessary to set the RadGridView.AllowRowReorder property to true and start reordering the rows.
Figure 1: Drag and drop in bound mode
Drag and Drop in Bound Mode
When RadGridView is in bound mode, drag and drop functionality is not supported out of the box because of the specificity of the DataSource collection of the source and target grid. However, such a functionality can be easily achieved by the RadGridViewDragDropService.
As a descendant of RadDragDropService, RadGridViewDragDropService handles the whole drag and drop operation. The PreviewDragOver event allows you to control on what targets the row being dragged can be dropped on. The PreviewDragDrop event allows you to get a handle on all the aspects of the drag and drop operation, the source (drag) grid, the destination (target) control, as well as the row being dragged. This is where we will initiate the actual physical move of the row(s) from one grid to the target control. A sample implementation is demonstrated in the Rows >> Drag and drop help article.
Register a custom RadGridViewDragDropService
RadGridView provides a convenient API to replace the default RadGridViewDragDropService instance with your custom one in case you need to introduce some custom logic.
1. Create a class that inherits RadGridViewDragDropService and override its Name property:
public class CustomDragDropService : RadGridViewDragDropService
{
public CustomDragDropService(RadGridViewElement gridViewElement)
: base(gridViewElement)
{
}
public override string Name
{
get
{
return typeof(RadGridViewDragDropService).Name;
}
}
}
Public Class CustomDragDropService
Inherits RadGridViewDragDropService
Public Sub New(gridViewElement As RadGridViewElement)
MyBase.New(gridViewElement)
End Sub
Public Overrides ReadOnly Property Name() As String
Get
Return GetType(RadGridViewDragDropService).Name
End Get
End Property
End Class
2. After you have already overridden the desired methods in order to achieve the expected behavior register the custom service to RadGridView:
CustomDragDropService customService = new CustomDragDropService(radGridView1.GridViewElement);
radGridView1.GridViewElement.RegisterService(customService);
Dim customService As New CustomDragDropService(radGridView1.GridViewElement)
radGridView1.GridViewElement.RegisterService(customService)