/// <summary>
/// Occurs when the navigation item has changed
/// </summary>
/// <param name="oldValue"></param>
/// <param name="newValue"></param>
protected override void OnNavigationItemChanged(NavigationItem oldValue, NavigationItem newValue)
{
base.OnNavigationItemChanged(oldValue, newValue);
if (this.Frame == null || newValue == null)
{
this.SelectedItem = null;
return;
}
string layoutStateName = LayoutStateMasterDetail;
if (newValue.IsLeaf())
{
// select navigation item itself
this.SelectedItem = newValue;
layoutStateName = LayoutStateDetail;
}
else if (this.SelectedItem == null)
{
// auto-select first child (if not set)
this.SelectedItem = newValue.Items.FirstOrDefault();
}
VisualStateManager.GoToState(this, layoutStateName, false);
}
/// <summary>
/// Occurs when the selected item has changed.
/// </summary>
/// <param name="oldValue"></param>
/// <param name="newValue"></param>
protected override void OnSelectedItemChanged(NavigationItem oldValue, NavigationItem newValue)
{
if (newValue == null || this.lastSelectedItem == newValue)
{
return;
}
this.lastSelectedItem = newValue;
if (this.NavigationItem != newValue && ((!newValue.IsLeaf() || this.WindowState == WindowStateNarrow)))
{
// navigate to selected item
base.OnSelectedItemChanged(oldValue, newValue);
}
else
{
// navigate to content and supply the PageParameter
var pageType = newValue.PageType ?? typeof(Page);
if (pageType != typeof(Page) || this.ContentFrame.SourcePageType != pageType)
{
this.ContentFrame.Navigate(pageType, newValue.PageParameter);
}
}
}
/// <summary>
/// Determines whether specified item should be shown in the master-detail view, given the current state
/// </summary>
/// <param name="item"></param>
/// <returns></returns>
protected bool IsMasterDetailCandidate(NavigationItem item)
{
return(!item.IsRoot() && (item.IsLeaf() || (!item.HasGrandchildren() && this.WindowState == WindowStateWide)));
}
