How is routing carried out in the MVC pattern? The routing mechanism in ASP.NET MVC is responsible for determining which controller and action should handle a particular request based on the URL of the request. The routing process typically involves the following steps: Incoming Request: When a user makes a request to our ASP.NET MVC application by entering a URL in the browser, the request is received by the ASP.NET runtime. ...
Accessing Services in Views 1. Using Dependency Injection in Views with Razor Pages To use services directly in Razor Pages, follow these steps: 1.1. Register Services in Startup.cs Ensure your service is registered in the DI container within Startup.cs (or Program.cs in .NET 6 and later). 1 2 3 4 5 public void ConfigureServices(IServiceCollection services) { services.AddRazorPages(); services.AddScoped<IMyService, MyService>(); // Register your service } 1.2. Inject Services into the View In Razor Pages (.cshtml files), you can inject services directly into the page using the @inject directive. ...
Basic Implementation 1 2 3 4 5 6 7 8 9 10 Singleton singleton = Singleton.Instance; sealed class Singleton { public static Singleton Instance { get; } = new(); private Singleton() { } } Null Checking 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Singleton singleton = Singleton.Instance; sealed class Singleton { private static Singleton _instance = default!; public static Singleton Instance { get { if (_instance is null) { _instance = new Singleton(); } return _instance; } } private Singleton() { Console.WriteLine("Instantiating singleton"); } } Thread Safe 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 Singleton singleton = Singleton.Instance; sealed class Singleton { private static Singleton _instance = default!; private static object _lock = new(); public static Singleton Instance { get { if (_instance is null) { Console.WriteLine("Locking"); lock (_lock) { if (_instance is null) { _instance = new Singleton(); } } } return _instance; } } private Singleton() { Console.WriteLine("Instantiating singleton"); } } using Dotnet Base Class Library (BCL) 1 2 3 4 5 6 7 8 9 10 11 12 13 Singleton singleton = Singleton.Instance; sealed class Singleton { private static readonly Lazy<Singleton> _lazyInstance = new(() => new()); public static Singleton Instance => _lazyInstance.Value; private Singleton() { Console.WriteLine("Instantiating singleton"); } } Jon Skeet way 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Singleton singleton = Singleton.Instance; sealed class Singleton { public static string ClassName; public static Singleton Instance => Nested.Instance; private class Nested { internal static Singleton Instance { get; } = new(); static Nested() { } } private Singleton() { } static Singleton() { ClassName = "asdf"; } } Using Microsoft Dependency Injection Package 1 2 3 <ItemGroup> <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" /> </ItemGroup> 1 2 3 4 5 6 7 8 9 10 11 12 13 using Microsoft.Extensions.DependencyInjection; IServiceCollection services = new ServiceCollection(); services.AddSingleton<Singleton>(); var serviceProvider = services.BuildServiceProvider(); var instance = serviceProvider.GetRequiredService<Singleton>(); class Singleton() { }
Data Passing Between Controller and View Using Form Like POST Method ViewBag.Number and (int)ViewData[“Number”] from controller to View Controller to Controller TempData 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 public ActionResult SubmitForm(MyModel model) { if (ModelState.IsValid) { // Process the form data // Store a success message in TempData TempData["Message"] = "Form submitted successfully!"; // Redirect to another action return RedirectToAction("Confirmation"); } return View(model); } public ActionResult Confirmation() { // Retrieve the message from TempData ViewBag.Message = TempData["Message"]; return View(); } 1. Using ViewData ViewData is a dictionary-based way to pass data to the view. It uses the ViewDataDictionary class and is accessed by string keys. ...