c# - 无法在 IDistributedCache 中等待 SetStringAsync

Question

我正在使用 .NET Core 2.0 和 Microsoft.Extensions.Caching.Redis 2.0。为什么 IDistributedCache.SetStringAsync 实际上没有标记为异步，因此不可等待？

        var services = new ServiceCollection();
        services.AddDistributedRedisCache(options =>
        {
            options.Configuration = "127.0.0.1";
            options.InstanceName = "master";
        });

        var provider = services.BuildServiceProvider();

        var cache = provider.GetService<IDistributedCache>();

        // Does not compile
        await cache.SetStringAsync("mykey", "myvalue");

Answer 1

这些方法被定义为返回 Task (它们是 DistributedCacheExtensions 中的扩展方法):

 public static Task SetStringAsync(this IDistributedCache cache, string key, string value)
 {
     return cache.SetStringAsync(key, value, new DistributedCacheEntryOptions());
 }

你可以使用 await用这样的方法(MSDN)

The task to which the await operator is applied typically is returned by a call to a method that implements the Task-Based Asynchronous Pattern. They include methods that return Task, Task<TResult>, and System.Threading.Tasks.ValueType<TResult> objects.

但是你不能使用await在未标记为 async 的方法中，这就是你有编译错误的原因:

await can only be used in an asynchronous method modified by the async keyword.

---

如果您对团队标记为 SetStringAsync 会有什么不同感兴趣作为异步方法，例如:

public static async Task SetStringAsync

然后查看 SO "async Task then await Task" vs "Task then return task"