//Slight tweak on the above method to make it async and allow use with a serviceProvider instead of a host, and with a type argument instead of generic argument so it can be called at run time
//The above methos only needs host for it's services so it could be refactored.
//The above method only needs <t> so it can be used as a type in an overload of the method it calls.
//This version also allows an optional set of parameters
//The only downside is you can't have design/compiletime type safety
//There's a lot of duplicate code between the two, can probably refactor the core of the method into a separate method that they both call
public static async Task <IComponent> AddComponent(this IServiceProvider services, XF.Element parent, Type type, System.Collections.Generic.Dictionary <string, object> parameters = null)
{
if (services is null)
{
throw new ArgumentNullException(nameof(services));
}
if (parent is null)
{
throw new ArgumentNullException(nameof(parent));
}
if (type is null)
{
throw new ArgumentNullException(nameof(type));
}
if (!typeof(IComponent).IsAssignableFrom(type))
{
throw new InvalidOperationException($"Cannot add {type.Name} to {parent.GetType().Name}. {type.Name} is not an IComponent. If you are trying to add a Xamarin.Forms type, try adding the Mobile Blazor Bindings equivalent instead.");
}
#pragma warning disable CA2000 // Dispose objects before losing scope
var renderer = new MobileBlazorBindingsRenderer(services, services.GetRequiredService <ILoggerFactory>());
#pragma warning restore CA2000 // Dispose objects before losing scope
return(await renderer.AddComponent(type, CreateHandler(parent, renderer), parameters).ConfigureAwait(false));
}
internal async Task <XF.Page> BuildPage(Type componentType)
{
var container = new RootContainerHandler();
var route = NavigationParameters[componentType];
#pragma warning disable CA2000 // Dispose objects before losing scope. Renderer is disposed when page is closed.
var renderer = new MobileBlazorBindingsRenderer(_services, _services.GetRequiredService <ILoggerFactory>());
#pragma warning restore CA2000 // Dispose objects before losing scope
var addComponentTask = renderer.AddComponent(componentType, container, route.Parameters);
var elementAddedTask = container.WaitForElementAsync();
await Task.WhenAny(addComponentTask, elementAddedTask).ConfigureAwait(false);
if (container.Elements.Count != 1)
{
throw new InvalidOperationException("The target component of a Shell navigation must have exactly one root element.");
}
var page = container.Elements.FirstOrDefault() as XF.Page
?? throw new InvalidOperationException("The target component of a Shell navigation must derive from the Page component.");
DisposeRendererWhenPageIsClosed(renderer, page);
return(page);
}
private static ElementHandler CreateHandler(XF.Element parent, MobileBlazorBindingsRenderer renderer)
{
return(parent switch
{
XF.ContentPage contentPage => new ContentPageHandler(renderer, contentPage),
XF.ContentView contentView => new ContentViewHandler(renderer, contentView),
XF.Label label => new LabelHandler(renderer, label),
XF.FlyoutPage flyoutPage => new FlyoutPageHandler(renderer, flyoutPage),
XF.ScrollView scrollView => new ScrollViewHandler(renderer, scrollView),
XF.ShellContent shellContent => new ShellContentHandler(renderer, shellContent),
XF.Shell shell => new ShellHandler(renderer, shell),
XF.ShellItem shellItem => new ShellItemHandler(renderer, shellItem),
XF.ShellSection shellSection => new ShellSectionHandler(renderer, shellSection),
XF.TabbedPage tabbedPage => new TabbedPageHandler(renderer, tabbedPage),
_ => new ElementHandler(renderer, parent),
});
/// <summary>
/// Creates a component of type <typeparamref name="TComponent"/> and adds it as a child of <paramref name="parent"/>.
/// </summary>
/// <typeparam name="TComponent"></typeparam>
/// <param name="host"></param>
/// <param name="parent"></param>
public static void AddComponent <TComponent>(this IHost host, XF.Element parent) where TComponent : IComponent
{
if (host is null)
{
throw new ArgumentNullException(nameof(host));
}
if (parent is null)
{
throw new ArgumentNullException(nameof(parent));
}
var services = host.Services;
var renderer = new MobileBlazorBindingsRenderer(services, services.GetRequiredService <ILoggerFactory>());
// TODO: This call is an async call, but is called as "fire-and-forget," which is not ideal.
// We need to figure out how to get Xamarin.Forms to run this startup code asynchronously, which
// is how this method should be called.
renderer.AddComponent <TComponent>(new ElementHandler(renderer, parent)).ConfigureAwait(false);
}
private void DisposeRendererWhenPageIsClosed(MobileBlazorBindingsRenderer renderer, XF.Page page)
{
// Unfortunately, XF does not expose any Destroyed event for elements.
// Therefore we subscribe to Navigated event, and consider page as destroyed
// if it is not present in the navigation stack.
XF.Shell.Current.Navigated += DisposeWhenNavigatedAway;
void DisposeWhenNavigatedAway(object sender, XF.ShellNavigatedEventArgs args)
{
// We need to check all navigationStacks for all Shell items.
var currentPages = XF.Shell.Current.Items
.SelectMany(i => i.Items)
.SelectMany(i => i.Navigation.NavigationStack);
if (!currentPages.Contains(page))
{
XF.Shell.Current.Navigated -= DisposeWhenNavigatedAway;
renderer.Dispose();
}
}
}
