private static DragDropPreview GetDragDropPreview(IDragInfo dragInfo, UIElement visualTarget, UIElement sender)
{
var visualSource = dragInfo?.VisualSource;
if (visualSource is null)
{
return(null);
}
var hasDragDropPreview = DragDropPreview.HasDragDropPreview(dragInfo, visualTarget ?? visualSource, sender);
if (hasDragDropPreview)
{
var rootElement = TryGetRootElementFinder(sender).FindRoot(visualTarget ?? visualSource);
var preview = new DragDropPreview(rootElement, dragInfo, visualTarget ?? visualSource, sender);
if (preview.Child != null)
{
preview.IsOpen = true;
return(preview);
}
}
return(null);
}
private static DragDropPreview GetDragDropPreview(DropInfo dropInfo, UIElement target)
{
var dragInfo = dropInfo.DragInfo;
var template = GetDropAdornerTemplate(dropInfo.VisualTarget) ?? GetDragAdornerTemplate(dragInfo.VisualSource);
var templateSelector = GetDropAdornerTemplateSelector(dropInfo.VisualTarget) ?? GetDragAdornerTemplateSelector(dragInfo.VisualSource);
UIElement adornment = null;
var useDefaultDragAdorner = template == null && templateSelector == null && GetUseDefaultDragAdorner(dragInfo.VisualSource);
var useVisualSourceItemSizeForDragAdorner = GetUseVisualSourceItemSizeForDragAdorner(dragInfo.VisualSource);
if (useDefaultDragAdorner)
{
template = dragInfo.VisualSourceItem.GetCaptureScreenDataTemplate(dragInfo.VisualSourceFlowDirection);
}
if (template != null || templateSelector != null)
{
if (dragInfo.Data is IEnumerable && !(dragInfo.Data is string))
{
if (!useDefaultDragAdorner && ((IEnumerable)dragInfo.Data).Cast <object>().Count() <= 10)
{
var itemsControl = new ItemsControl();
itemsControl.ItemsSource = (IEnumerable)dragInfo.Data;
itemsControl.ItemTemplate = template;
itemsControl.ItemTemplateSelector = templateSelector;
itemsControl.Tag = dragInfo;
if (useVisualSourceItemSizeForDragAdorner)
{
var bounds = VisualTreeHelper.GetDescendantBounds(dragInfo.VisualSourceItem);
itemsControl.SetValue(FrameworkElement.MinWidthProperty, bounds.Width);
}
// The ItemsControl doesn't display unless we create a grid to contain it.
// Not quite sure why we need this...
var grid = new Grid();
grid.Children.Add(itemsControl);
adornment = grid;
}
}
else
{
var contentPresenter = new ContentPresenter();
contentPresenter.Content = dragInfo.Data;
contentPresenter.ContentTemplate = template;
contentPresenter.ContentTemplateSelector = templateSelector;
contentPresenter.Tag = dragInfo;
if (useVisualSourceItemSizeForDragAdorner)
{
var bounds = VisualTreeHelper.GetDescendantBounds(dragInfo.VisualSourceItem);
contentPresenter.SetValue(FrameworkElement.MinWidthProperty, bounds.Width);
contentPresenter.SetValue(FrameworkElement.MinHeightProperty, bounds.Height);
}
adornment = contentPresenter;
}
}
if (adornment != null)
{
if (useDefaultDragAdorner)
{
adornment.Opacity = GetDefaultDragAdornerOpacity(dragInfo.VisualSource);
}
var rootElement = TryGetRootElementFinder(target).FindRoot(dropInfo.VisualTarget ?? dragInfo.VisualSource);
var preview = new DragDropPreview(rootElement, adornment, GetDragAdornerTranslation(dragInfo.VisualSource), GetDragMouseAnchorPoint(dragInfo.VisualSource))
{
IsOpen = true
};
return(preview);
}
return(null);
}