public Task StartAsync(CancellationToken cancellationToken = default)
{
// We need to do this as early as possible, it eliminates a bunch of problems. Note that what we do
// is a bit fragile. If you see things breaking because JSRuntime.Current isn't set, then it's likely
// that something on the startup path went wrong.
//
// We want to the JSRuntime created here to be the 'ambient' runtime when JS calls back into .NET. When
// this happens in the browser it will be a direct call from Mono. We effectively needs to set the
// JSRuntime in the 'root' execution context which implies that we want to do as part of a direct
// call from Program.Main, and before any 'awaits'.
JSRuntime.SetCurrentJSRuntime(_runtime);
SetBrowserHttpMessageHandlerAsDefault();
var scopeFactory = Services.GetRequiredService <IServiceScopeFactory>();
_scope = scopeFactory.CreateScope();
try
{
var startup = _scope.ServiceProvider.GetService <IBlazorStartup>();
if (startup == null)
{
var message =
$"Could not find a registered Blazor Startup class. " +
$"Using {nameof(IWebAssemblyHost)} requires a call to {nameof(IWebAssemblyHostBuilder)}.UseBlazorStartup.";
throw new InvalidOperationException(message);
}
// Note that we differ from the WebHost startup path here by using a 'scope' for the app builder
// as well as the Configure method.
var builder = new WebAssemblyBlazorApplicationBuilder(_scope.ServiceProvider);
startup.Configure(builder, _scope.ServiceProvider);
_renderer = builder.CreateRenderer();
}
catch
{
_scope.Dispose();
_scope = null;
if (_renderer != null)
{
_renderer.Dispose();
_renderer = null;
}
throw;
}
return(Task.CompletedTask);
}
public void ConventionBasedStartup_Configure()
{
// Arrange
var instance = new MyStartup8();
var startup = new ConventionBasedStartup(instance);
var services = new ServiceCollection().AddSingleton("foo").BuildServiceProvider();
var builder = new WebAssemblyBlazorApplicationBuilder(services);
// Act
startup.Configure(builder, services);
// Assert
Assert.Collection(
instance.Arguments,
a => Assert.Same(builder, a),
a => Assert.Equal("foo", a));
}
