RadTaskBoard.DragDropBehavior

[Brian]

I'm trying to implement the custom Drag Drop behavior depicted at this link: https://docs.telerik.com/devtools/wpf/controls/radtaskboard/features/taskboardcolumndragdropbehavior#taskboardcolumndragdropbehavior

 However I cannot get the XAML to recognize this item 

<telerik:RadTaskBoard.DragDropBehavior>

 

The error message is 'The member "DragDropBehavior" is not recognized or is not accessible.

Regards,

[Martin Ivanov]

Hello  Brian,

The drag drop behavior is available since the R1 2020 SP1 version. Please double check if you are using this or a later version of Telerik UI for WPF.

Regards,
Martin Ivanov
Progress Telerik

[Brian]

So that it may help others, the way to get this to work is implement a class that derives from TaskBoardColumnDragDropBehavior. Then override the methods that you need.

using Telerik.Windows.Controls.TaskBoard;
using Telerik.Windows.DragDrop.Behaviors;

public class TaskDragBehavior : TaskBoardColumnDragDropBehavior
{

    //CanStartDrag DragDropState Type: Telerik.Windows.DragDrop.Behaviors.DragDropState
    //CanDrop DragDropState Type: Telerik.Windows.Controls.TaskBoard.TaskBoardColumnDragDropState
    //DragDropCompleted DragDropState Type: Telerik.Windows.Controls.TaskBoard.TaskBoardColumnDragDropState
    //Drop DragDropState Type: Telerik.Windows.Controls.TaskBoard.TaskBoardColumnDragDropState
    //IsMovingItems DragDropState Type: Telerik.Windows.Controls.TaskBoard.TaskBoardColumnDragDropState
    //DragDropCanceled DragDropState Type: Telerik.Windows.Controls.TaskBoard.TaskBoardColumnDragDropState


    public TaskDragBehavior()
        : base()
    {

    }

    public override bool CanDrop(DragDropState state)
    {
        var dds = state as TaskBoardColumnDragDropState;
        return base.CanDrop(state);
    }

    public override bool CanStartDrag(DragDropState state)
    {
        return base.CanStartDrag(state);
    }

    protected override IEnumerable<object> CopyDraggedItems(DragDropState state)
    {
        return base.CopyDraggedItems(state);
    }

    public override void DragDropCanceled(DragDropState state)
    {
        var dds = state as TaskBoardColumnDragDropState;
        base.DragDropCanceled(state);
    }

    public override void DragDropCompleted(DragDropState state)
    {
        var dds = state as TaskBoardColumnDragDropState;
        base.DragDropCompleted(state);
    }

    public override void Drop(DragDropState state)
    {
        var dds = state as TaskBoardColumnDragDropState;
        base.Drop(state);
    }

    protected override bool IsMovingItems(DragDropState state)
    {
        return base.IsMovingItems(state);
    }

}

 

Then in XAML you will need to implement the Drag Drop behavior.

<telerik:RadTaskBoard
    x:Name="taskBoard"
    GroupMemberPath="StatusGroup"
    AutoGenerateColumns="False"
    ItemsSource="{Binding MyTasks}"
    SelectedItem="{Binding SelectedModel}"
    >
    <-- Add the custon Drag Drop Behavior that you created. -->
    <telerik:RadTaskBoard.DragDropBehavior>
        <local1:TaskDragBehavior/>
    </telerik:RadTaskBoard.DragDropBehavior>


    <telerik:TaskBoardColumn Header="Backlog" GroupName="Backlog"/>
    <telerik:TaskBoardColumn Header="Hold" GroupName="Hold"/>
    <telerik:TaskBoardColumn Header="Active" GroupName="Active"/>
    <telerik:TaskBoardColumn Header="Completed" GroupName="Completed"/>
    <telerik:TaskBoardColumn Header="Cancelled" GroupName="Cancelled"/>

</telerik:RadTaskBoard>

 

After that all of the drag / drop events will be re-directed to the overridden handlers.

 

Regards,