Microsoft.Windows.Controls.Ribbon.RibbonGallery.CoerceSelectedValue C# (CSharp) Méthode

        private static object CoerceSelectedValue(DependencyObject d, object value)
        {
            RibbonGallery gallery = (RibbonGallery)d;

            if (!gallery.IsSelectionChangeActive)
            {
                object oldValue = gallery.SelectedValue;
                object newValue = value;

                if (!VerifyEqual(oldValue, newValue))
                {
                    if (newValue != null)
                    {
                        object newItem;
                        RibbonGalleryCategory category = null;
                        RibbonGalleryItem galleryItem = null;

                        // If the newValue doesn't exist in RibbonGallery under any category then return UnsetValue
                        // so as not to change existing value
                        bool ignoreItemContainerGeneratorStatus = false;
                        if (!gallery.ContainsValue(value, ignoreItemContainerGeneratorStatus, out newItem, out category, out galleryItem))
                        {
                            return DependencyProperty.UnsetValue;
                        }

                        // Changes the selection to newItem
                        gallery.SelectedItem = newItem;
                    }
                    else
                    {
                        // Deselect
                        gallery.SelectedItem = null;
                    }
                }
                else if (gallery.ShouldForceCoerceSelectedValue)
                {
                    object newItem;
                    RibbonGalleryCategory category = null;
                    RibbonGalleryItem galleryItem = null;

                    // This block is called when generating RibbonGalleryCategory containers
                    // to synchronize the SelectedItem with the previously specified SelectedValue.
                    // If a match isn't found yet we keep the oldValue as is by returning UnsetValue.
                    bool ignoreItemContainerGeneratorStatus = true;
                    if (!gallery.ContainsValue(value, ignoreItemContainerGeneratorStatus, out newItem, out category, out galleryItem))
                    {
                        return DependencyProperty.UnsetValue;
                    }
                    gallery.SelectedItem = newItem;
                }
            }

            return value;
        }