majiayu000 Async Programming Essentials
1. Task vs ValueTask
// General async: Use Task
public async Task<Data> LoadAsync() { }
// Frequent cache hits: Use ValueTask
public ValueTask<Data> GetAsync(string key)
{
if (_cache.TryGetValue(key, out var cached))
return new ValueTask<Data>(cached);
return new ValueTask<Data>(LoadFromDbAsync(key));
}
2. CancellationToken
public async Task<Data> LoadAsync(CancellationToken ct = default)
{
ct.ThrowIfCancellationRequested();
return await _httpClient.GetFromJsonAsync<Data>(url, ct);
}
// Timeout
using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
await LongOperationAsync(cts.Token);
3. Anti-patterns
// ❌ No async void
public async void BadMethod() { }
// ❌ No .Result, .Wait() (deadlock)
var result = GetDataAsync().Result;
// ✅ Use await
var result = await GetDataAsync();
For details: See
/dotnet-asyncskill