/// <summary>
/// Invoked when this page is about to be displayed in a Frame.
/// This method calls <see cref="LoadState"/>, where all page specific
/// navigation and process lifetime management logic should be placed.
/// </summary>
/// <param name="e">Event data that describes how this page was reached. The Parameter
/// property provides the group to be displayed.</param>
public void OnNavigatedTo(NavigationEventArgs e)
{
var frameState = SuspensionManager.SessionStateForFrame(Frame);
_pageKey = "Page-" + Frame.BackStackDepth;
if (e.NavigationMode == NavigationMode.New)
{
// Clear existing state for forward navigation when adding a new page to the
// navigation stack
var nextPageKey = _pageKey;
int nextPageIndex = Frame.BackStackDepth;
while (frameState.Remove(nextPageKey))
{
nextPageIndex++;
nextPageKey = "Page-" + nextPageIndex;
}
// Pass the navigation parameter to the new page
LoadState?.Invoke(this, new LoadStateEventArgs(e.Parameter, null));
}
else
{
// Pass the navigation parameter and preserved page state to the page, using
// the same strategy for loading suspended state and recreating pages discarded
// from cache
LoadState?.Invoke(this, new LoadStateEventArgs(e.Parameter, (Dictionary <String, Object>)frameState[_pageKey]));
}
SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility = CanGoBack() ? AppViewBackButtonVisibility.Visible : AppViewBackButtonVisibility.Collapsed;
}
/// <summary>
/// Invoked when this page is about to be displayed in a Frame.
/// This method calls <see cref="LoadState" />, where all page specific
/// navigation and process lifetime management logic should be placed.
/// </summary>
/// <param name="e">
/// Event data that describes how this page was reached. The Parameter
/// property provides the group to be displayed.
/// </param>
public virtual void OnNavigatedTo(NavigationEventArgs e)
{
var frameState = GetSessionState();
_pageKey = e.Parameter as string ?? "Page-" + Frame.BackStackDepth;
if (e.NavigationMode == NavigationMode.New)
{
// Clear existing state for forward navigation when adding a new page to the
// navigation stack
var nextPageKey = _pageKey;
var nextPageIndex = Frame.BackStackDepth;
while (frameState.Remove(nextPageKey))
{
nextPageIndex++;
nextPageKey = "Page-" + nextPageIndex;
}
// Pass the navigation parameter to the new page
LoadState?.Invoke(this, new LoadStateEventArgs(e.Parameter, null));
}
else
{
var state = (Dictionary <string, object>)frameState[_pageKey];
//NOTE loading state of view model.
UwpToolkitExtensions.ApplicationStateManager.OnLoadState(Page, state, e);
// Pass the navigation parameter and preserved page state to the page, using
// the same strategy for loading suspended state and recreating pages discarded
// from cache
LoadState?.Invoke(this, new LoadStateEventArgs(e.Parameter, state));
}
}
internal Frame(IChannelOwner parent, string guid, FrameInitializer initializer) : base(parent, guid)
{
_channel = new FrameChannel(guid, parent.Connection, this);
_initializer = initializer;
Url = _initializer.Url;
Name = _initializer.Name;
ParentFrame = _initializer.ParentFrame;
_loadStates = initializer.LoadStates;
_channel.LoadState += (sender, e) =>
{
lock (_loadStates)
{
if (e.Add.HasValue)
{
_loadStates.Add(e.Add.Value);
LoadState?.Invoke(this, new LoadStateEventArgs {
LifecycleEvent = e.Add.Value
});
}
if (e.Remove.HasValue)
{
_loadStates.Remove(e.Remove.Value);
}
}
};
_channel.Navigated += (sender, e) =>
{
Url = e.Url;
Name = e.Name;
Navigated?.Invoke(this, e);
if (string.IsNullOrEmpty(e.Error))
{
((Page)Page)?.OnFrameNavigated(this);
}
};
}
internal override void OnMessage(string method, JsonElement?serverParams)
{
switch (method)
{
case "navigated":
var e = serverParams?.ToObject <FrameNavigatedEventArgs>(Connection.GetDefaultJsonSerializerOptions());
if (serverParams.Value.TryGetProperty("newDocument", out var documentElement))
{
e.NewDocument = documentElement.ToObject <NavigateDocument>(Connection.GetDefaultJsonSerializerOptions());
}
Navigated?.Invoke(this, e);
break;
case "loadstate":
LoadState?.Invoke(
this,
serverParams?.ToObject <FrameChannelLoadStateEventArgs>(Connection.GetDefaultJsonSerializerOptions()));
break;
}
}
public void OnNavigatedTo(NavigationEventArgs e)
{
var frameState = SuspensionManager.SessionStateForFrame(this.Frame);
_pageKey = "Page-" + Frame.BackStackDepth;
if (e.NavigationMode == NavigationMode.New)
{
var nextPageKey = this._pageKey;
int nextPageIndex = this.Frame.BackStackDepth;
while (frameState.Remove(nextPageKey))
{
nextPageIndex++;
nextPageKey = "Page-" + nextPageIndex;
}
LoadState?.Invoke(this, new LoadStateEventArgs(e.Parameter, null));
}
else
{
LoadState?.Invoke(this, new LoadStateEventArgs(e.Parameter, (Dictionary <String, Object>)frameState[this._pageKey]));
}
}