public async Task Navigate(string viewKey, object args)
{
using (var releaser = await _lock.LockAsync())
{
// Do not navigate to the same view.
if (viewKey == _navigationContainer.CurrentViewKey)
{
return;
}
_navigationContainer.CurrentViewKey = viewKey;
if (_viewsByKey.ContainsKey(viewKey))
{
var type = _viewsByKey[viewKey];
var view = await _viewService.Build(type, args) as IView;
if (view == null)
{
throw new Exception(String.Format("Unable to build view {0}", type.ToString()));
}
if (_navigationContainer == null)
{
throw new Exception($"{nameof(INavigationContainer)} is null. Did you forget to call NavigationService.Init()?");
}
_navigationContainer.SetNavigationBar(false, view); //TODO: read from stack
var model = view.BindingContext as IViewModel;
if (model != null)
{
view.Appearing += (s, e) => { model.OnAppearing(); };
view.Disappearing += (s, e) => { model.OnDisappearing(); };
}
await _navigationContainer.PushAsync(view);
ThreadHelper.RunOnUIThread(() =>
{
if (model != null)
{
model.OnNavigated(args); // Do not await.
}
});
}
else
{
throw new ArgumentException(
string.Format(
"No such key: {0}. Did you forget to call NavigationService.Map?",
viewKey),
"key");
}
}
}
