Sample of how to use IDragInfo.DataObject to use custom instances of IDataObject in gong-wpf-dragdrop.

DataObjectSample.cs

public class DataObjectSample : IDragSource
{
    public virtual void StartDrag(IDragInfo dragInfo)
    {
        var itemCount = dragInfo.SourceItems.Cast<object>().Count();

        if (itemCount == 1)
        {
            dragInfo.Data = dragInfo.SourceItems.Cast<object>().First();
        }
        else if (itemCount > 1)
        {
            dragInfo.Data = TypeUtilities.CreateDynamicallyTypedList(dragInfo.SourceItems);
        }

        dragInfo.Effects = (dragInfo.Data != null) ?
                               DragDropEffects.Copy | DragDropEffects.Move :
                               DragDropEffects.None;

        // This instance will be used in the drag/drop operation
        // Use a custom instance of IDataObject if there is something special needed
        // for your drag/drop operation.
        // This instance needs to be able to handle SetData so the framework can set
        // the objects being transferred
        dragInfo.DataObject = new DataObject();
    }

    public virtual void Dropped(IDropInfo dropInfo)
    {
    }
}