private void UpdateSelection()
{
LinkGroup selectedGroup = null;
Link selectedLink = null;
Uri sourceNoFragment = NavigationHelper.RemoveFragment(this.SelectedSource);
if (this.LinkGroups != null)
{
// find the current select group and link based on the selected source
var linkInfo = (from g in this.LinkGroups
from l in g.Links
where l.Source == sourceNoFragment
select new {
Group = g,
Link = l
}).FirstOrDefault();
if (linkInfo != null)
{
selectedGroup = linkInfo.Group;
selectedLink = linkInfo.Link;
}
else
{
// could not find link and group based on selected source, fall back to selected link group
selectedGroup = this.SelectedLinkGroup;
// if selected group doesn't exist in available groups, select first group
if (!this.LinkGroups.Any(g => g == selectedGroup))
{
selectedGroup = this.LinkGroups.FirstOrDefault();
}
}
}
ReadOnlyLinkGroupCollection groups = null;
if (selectedGroup != null)
{
// ensure group itself maintains the selected link
selectedGroup.SelectedLink = selectedLink;
// find the collection this group belongs to
var groupKey = GetGroupKey(selectedGroup);
this.groupMap.TryGetValue(groupKey, out groups);
}
this.isSelecting = true;
// update selection
SetValue(VisibleLinkGroupsPropertyKey, groups);
SetCurrentValue(SelectedLinkGroupProperty, selectedGroup);
SetCurrentValue(SelectedLinkProperty, selectedLink);
this.isSelecting = false;
}
/// <summary>
/// Gets a non-null key for given group.
/// </summary>
/// <param name="group"></param>
/// <returns></returns>
private static string GetGroupKey(LinkGroup group)
{
// use special key for GroupKey <null>
return(group.GroupKey ?? "<null>");
}
