c# - 当服务具有其他依赖项时，无法让注入(inject)在 Azure Functions 中工作

Question

我有一个服务CompanyService

此服务依赖于另外 2 个服务 - ICompanyRepository 和 IDataCacheService

public class CompanyService : ICompanyService
{
    private readonly ICompanyRepository _companyRepository;
    private IDataCacheService _dataCacheService;

    public CompanyService(ICompanyRepository companyRepository, IDataCacheService dataCacheService)
    {
        _companyRepository = companyRepository;
        _dataCacheService = dataCacheService;
    }
}

该服务本身没有依赖项

现在我需要通过 Azure 函数中的内置注入(inject)来使其可用

因此，在 Startup.cs 中，我修改了 Configure 以添加新服务

public override void Configure(IFunctionsHostBuilder builder)
{
    var cosmosDbConnectionString = new CosmosDBConnectionString(Environment.GetEnvironmentVariable("CosmosDBConnection"));
    builder.Services.AddSingleton<IDocumentClient>(s =>
       new DocumentClient(cosmosDbConnectionString.ServiceEndpoint, cosmosDbConnectionString.AuthKey));

    var companyRepository = new CompanyRepository();
    builder.Services.AddSingleton<ICompanyRepository>(companyRepository);

    var dataCacheService = new DataCacheService();
    builder.Services.AddSingleton<IDataCacheService>(dataCacheService);

    var companyService = new CompanyService(companyRepository, dataCacheService);

    builder.Services.AddSingleton<ICompanyService>(companyService);
}

编译并运行良好

但是，当我添加 ICompanyService 作为函数的参数时，我收到错误

Cannot bind parameter 'companyService' to type ICompanyService

我的方法如下

public class Companies
{
    private const string OperationName = "OPERATION";

    [FunctionName(OperationName)]
    public async Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Function, "get", Route = "myroute/")]HttpRequest req,
        ICompanyService companyService,
        ILogger log)
    {
       //logic here
    }
}

这与我的项目中的其他函数运行方法相同

我做错了什么？

这也不适用于标准 AddSingleton 语法

builder.Services.AddSingleton<ICompanyService, CompanyService>();

保罗

Answer 1

根据所示配置，注册可以简化为

public override void Configure(IFunctionsHostBuilder builder) {
    var services = builder.Services;
    var cosmosDbConnectionString = new CosmosDBConnectionString(Environment.GetEnvironmentVariable("CosmosDBConnection"));
    services.AddSingleton<IDocumentClient>(s =>
       new DocumentClient(cosmosDbConnectionString.ServiceEndpoint, cosmosDbConnectionString.AuthKey));

    services.AddSingleton<ICompanyRepository, CompanyRepository>();        
    services.AddSingleton<IDataCacheService, DataCacheService>();    
    services.AddSingleton<ICompanyService, CompanyService>();
}

剩下的就是确保通过构造函数注入(inject)将所需的服务显式注入(inject)到函数实例中。

public class Companies {
    private const string OperationName = "OPERATION";
    private readonly ICompanyService companyService;

    public Companies(ICompanyService companyService) {
        this.companyService = companyService;
    }

    [FunctionName(OperationName)]
    public async Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Function, "get", Route = "myroute/")]HttpRequest req,
        ILogger log) {
       //logic here
    }
}

引用Use dependency injection in .NET Azure Functions