Task based Asynchronous Pattern TAP
Context: The Task‑based Asynchronous Pattern (TAP) is the recommended asynchronous pattern in .NET. It uses Task and Task<T> to represent ongoing operations.
Introduction to async/await
Section titled “Introduction to async/await”Asynchronous programming allows your application to continue executing other work while waiting for long‑running operations (I/O, network calls, database queries). In C#, the async and await keywords make writing asynchronous code almost as simple as synchronous code, without blocking threads.
Why use async/await?
- Responsiveness: UI applications remain responsive during long operations.
- Scalability: Server applications handle more requests by freeing threads during I/O.
- Simplicity: Write asynchronous code that looks like synchronous code.
How to start: Add async to a method, then use await on tasks. The method must return Task, Task<T>, or void (only for event handlers).
// Synchronous version (blocks thread)string data = DownloadString(url);
// Asynchronous version (does not block)string data = await DownloadStringAsync(url);TAP pattern
Section titled “TAP pattern”A method following TAP returns a Task or Task<TResult> and is typically named with an Async suffix.
public Task<string> DownloadStringAsync(string url);public Task<int> GetUserCountAsync();Real-world usage example
Section titled “Real-world usage example”ASP.NET Core controllers: All controller actions can be async, improving scalability by not blocking threads during database calls.
Official documentation: