如你所见，你无法在服务注册过程中异步初始化服务。在这些情况下，我使用的解决方案不是直接创建服务，而是返回具有async Task<T> CreateAsync执行此操作方法的工厂或提供程序服务。你将此提供程序注册为服务，然后注入该提供程序并调用CreateAsync代码。这是一个例子：

using Microsoft.Azure.Cosmos;
using Microsoft.Azure.Cosmos.Fluent;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using System;
using System.Threading.Tasks;

namespace TestWebsite.Services
{
    public class CosmosDbProvider
    {
        /// <summary>
        /// Ctor: values provided by DI
        /// </summary>
        /// <param name="configuration"></param>
        /// <param name="logger"></param>
        public CosmosDbProvider(IConfiguration configuration, ILogger logger)
        {
            config = configuration;
            log = logger;
        }

        IConfiguration config;
        ILogger log;

        ICosmosDbService cachedService;

        public async Task<ICosmosDbService> CreateAsync()
        {
            // use a cached instance for all requests (similar to Lazy<T> but async)
            if (cachedService == null)
            {
                cachedService = await InitializeCosmosClientInstanceAsync();
            }
            return cachedService;
        }

        private async Task<CosmosDbService> InitializeCosmosClientInstanceAsync()
        {
            try
            {
                log.LogInformation("InitializeCosmosClientInstanceAsync started");

                // I'd recommend GetValue<T> for reading single values over GetSection
                string databaseName = config.GetValue<string>("DatabaseName");
                string containerRatings = config.GetValue<string>("ContainerRatings");
                string containerUsers = config.GetValue<string>("ContainerUsers");
                string containerLocations = config.GetValue<string>("ContainerLocations");

                string account = config.GetValue<string>("Account");
                string key = config.GetValue<string>("Key");

                log.LogDebug($"databaseName: {databaseName}");
                log.LogDebug($"containerRatings: {containerRatings}");
                log.LogDebug($"containerUsers: {containerUsers}");
                log.LogDebug($"containerLocations: {containerLocations}");
                // might not want to log sensitive info..
                // log.LogDebug($"account: {account}");
                // log.LogDebug($"key: {key}");

                log.LogDebug("Creating CosmosClientBuilder");
                CosmosClientBuilder clientBuilder = new CosmosClientBuilder(account, key);
                
                log.LogDebug("Creating CosmosClient");
                CosmosClient client = clientBuilder
                                    .WithConnectionModeDirect()
                                    .WithSerializerOptions(new CosmosSerializationOptions { PropertyNamingPolicy = CosmosPropertyNamingPolicy.Default })
                                    .Build();

                log.LogDebug("Creating CosmosDbService");
                CosmosDbService cosmosDbService = new CosmosDbService()
                {
                    ContainerRatings = client.GetContainer(databaseName, containerRatings),
                    ContainerRateLocationSmall = client.GetContainer(databaseName, containerLocations),
                    ContainerRateUser = client.GetContainer(databaseName, containerUsers),
                    CosmosClient = client,
                    DatabaseName = databaseName,
                    _logger = log
                };

                log.LogDebug($"CreateDatabase for '{databaseName}'");
                DatabaseResponse database = await client.CreateDatabaseIfNotExistsAsync(databaseName);
                
                log.LogDebug($"CreateContainer for '{containerRatings}'");
                await database.Database.CreateContainerIfNotExistsAsync(containerRatings, "/What");
                
                log.LogDebug($"CreateContainer for '{containerUsers}'");
                await database.Database.CreateContainerIfNotExistsAsync(containerUsers, "/UserName");

                log.LogDebug($"CreateContainer for '{containerLocations}'");
                await database.Database.CreateContainerIfNotExistsAsync(containerLocations, "/id");

                log.LogInformation("InitializeCosmosClientInstanceAsync completed");
                return cosmosDbService;

            }
            catch (Exception e)
            {
                log.LogError(e, "Failed when initializing CosmosDB");
                throw;
            }

        }
    }
}

我更改了配置代码以使用GetValue<T>-我认为它更简单，并添加了一堆日志记录语句。通常LogDebug在生产环境中是这样，你需要更改为调试级别（或者你可以根据需要更改为LogInformation）以帮助诊断问题。

在Startup.cs我们添加：

services.AddSingleton<CosmosDbProvider>();

要获取CosmosDB实例，请使用DI注入提供程序。然后，在控制器的Razor和Blazor页面中，你可以进行async呼叫：例如，示例Blazor页面Cosmos.razor

@page "/cosmos"
@inject TestWebsite.Services.CosmosDbProvider cosmosProvider;

<h3>Cosmos</h3>

@if(_db !=null)
{
    <p>Your database is called @_db.DatabaseName</p>
}

@code {

    TestWebsite.Services.ICosmosDbService _db;

    protected override async Task OnInitializedAsync()
    {
        // create/get CosmosDbService
        _db = await cosmosProvider.CreateAsync();
    }
}