ABP的依赖注入系统是基于Microsoft的依赖注入扩展库（Microsoft.Extensions.DependencyInjection nuget包）开发的。所以我们采用dotnet自带的注入方式也是支持的。
public class BlogModule : AbpModule
{
public override void ConfigureServices(ServiceConfigurationContext context)
{
//在此处注入依赖项
// dotnet自带依赖注入方式也是支持的
context.services.AddTransient
context.services.AddScoped
context.services.AddSingleton
}
}
Autofac 是.Net世界中最常用的依赖注入框架之一. 相比.Net Core标准的依赖注入库, 它提供了更多高级特性, 比如动态代理和属性注入.
1.安装 Volo.Abp.Autofac nuget 包到你的项目 (对于一个多项目应用程序, 建议安装到可执行项目或者Web项目中.)
2.模块添加 AbpAutofacModule 依赖:
[DependsOn(typeof(AbpAutofacModule))]
public class MyModule : AbpModule
{
//...
}
}
3.配置 AbpApplicationCreationOptions 用 Autofac 替换默认的依赖注入服务. 根据应用程序类型, 情况有所不同
public class Program
{
public static int Main(string[] args)
{
CreateHostBuilder(args).Build().Run();
}
internal static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureWebHostDefaults(webBuilder =>
{
webBuilder.UseStartup<Startup>();
})
.UseAutofac(); //Integrate Autofac!
}
namespace AbpConsoleDemo
{
class Program
{
static void Main(string[] args)
{
using (var application = AbpApplicationFactory.Create<AppModule>(options =>
{
options.UseAutofac(); //Autofac integration
}))
{
//...
}
}
}
}
如果实现这些接口,则会自动将类注册到依赖注入:
一些特定类型会默认注册到依赖注入.例子:
在某些情况下,你可能需要向IServiceCollection手动注册服务,尤其是在需要使用自定义工厂方法或singleton实例时.在这种情况下,你可以像Microsoft文档描述的那样直接添加服务.
public class BlogModule : AbpModule
{
public override void ConfigureServices(ServiceConfigurationContext context)
{
context.services.AddTransient<ITestMicrosoftManager, TestMicrosoftManager>();
}
}
public class MyService : ITransientDependency
{
public ILogger<MyService> Logger { get; set; }
public MyService()
{
Logger = NullLogger<MyService>.Instance;
}
public void DoSomething()
{
//...使用 Logger 写日志...
}
}
直接从IServiceProvider解析服务.在这种情况下,你可以将IServiceProvider注入到你的类并使用
public class MyService : ITransientDependency
{
private readonly IServiceProvider _serviceProvider;
public MyService(IServiceProvider serviceProvider)
{
_serviceProvider = serviceProvider;
}
public void DoSomething()
{
var taxCalculator = _serviceProvider.GetService<ITaxCalculator>();
//...
}
}
在某些情况下，需要替换某些接口的实现.
services.Replace(ServiceDescriptor.Transient<ITestManager, TestReplaceManager>());
[Dependency(ReplaceServices = true)]
[ExposeServices(typeof(ITestManager))]
public class TestReplaceManager : ITestManager, ITransientDependency
{
public void Print()
{
Console.WriteLine("TestReplaceManager");
}
}
public class DefaultTessAppService : ApplicationService, ITestAppService
{
// ....
}
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddApplication<xxxManagementHttpApiHostModule>();
}
}
public async static Task<IAbpApplicationWithExternalServiceProvider> CreateAsync(
[NotNull] Type startupModuleType,
[NotNull] IServiceCollection services,
Action<AbpApplicationCreationOptions>? optionsAction = null)
{
var app = new AbpApplicationWithExternalServiceProvider(startupModuleType, services, options =>
{
options.SkipConfigureServices = true;
optionsAction?.Invoke(options);
});
await app.ConfigureServicesAsync();
return app;
}
public virtual async Task ConfigureServicesAsync()
{
// 省略...
var assemblies = new HashSet<Assembly>();
//ConfigureServices
foreach (var module in Modules)
{
if (module.Instance is AbpModule abpModule)
{
if (!abpModule.SkipAutoServiceRegistration)
{
var assembly = module.Type.Assembly;
if (!assemblies.Contains(assembly))
{
Services.AddAssembly(assembly);
assemblies.Add(assembly);
}
}
}
try
{
await module.Instance.ConfigureServicesAsync(context);
}
catch (Exception ex)
{
throw new AbpInitializationException($"An error occurred during {nameof(IAbpModule.ConfigureServicesAsync)} phase of the module {module.Type.AssemblyQualifiedName}. See the inner exception for details.", ex);
}
}
// 省略...
}
4.进入下面AddAssembly下AddType的逻辑
public class DefaultConventionalRegistrar : ConventionalRegistrarBase
{
public override void AddType(IServiceCollection services, Type type)
{
if (IsConventionalRegistrationDisabled(type))
{
return;
}
// 查看是否有DependencyAttribute特性标签
var dependencyAttribute = GetDependencyAttributeOrNull(type);
// 判断是否有实现接口，注入对于的类型。
var lifeTime = GetLifeTimeOrNull(type, dependencyAttribute);
if (lifeTime == null)
{
return;
}
var exposedServiceTypes = GetExposedServiceTypes(type);
TriggerServiceExposing(services, type, exposedServiceTypes);
foreach (var exposedServiceType in exposedServiceTypes)
{
var serviceDescriptor = CreateServiceDescriptor(
type,
exposedServiceType,
exposedServiceTypes,
lifeTime.Value
);
if (dependencyAttribute?.ReplaceServices == true)
{
services.Replace(serviceDescriptor);
}
else if (dependencyAttribute?.TryRegister == true)
{
services.TryAdd(serviceDescriptor);
}
else
{
services.Add(serviceDescriptor);
}
}
}
}
// GetLifeTimeOrNull
protected virtual ServiceLifetime? GetLifeTimeOrNull(Type type, DependencyAttribute? dependencyAttribute)
{
return dependencyAttribute?.Lifetime ?? GetServiceLifetimeFromClassHierarchy(type) ?? GetDefaultLifeTimeOrNull(type);
}
// abp 三个生命周期
protected virtual ServiceLifetime? GetServiceLifetimeFromClassHierarchy(Type type)
{
if (typeof(ITransientDependency).GetTypeInfo().IsAssignableFrom(type))
{
return ServiceLifetime.Transient;
}
if (typeof(ISingletonDependency).GetTypeInfo().IsAssignableFrom(type))
{
return ServiceLifetime.Singleton;
}
if (typeof(IScopedDependency).GetTypeInfo().IsAssignableFrom(type))
{
return ServiceLifetime.Scoped;
}
return null;
}
5.重点到了,看下为什么名称错误为什么导致注入失败。
public class ExposeServicesAttribute : Attribute, IExposedServiceTypesProvider
{
// 省略...
private static List<Type> GetDefaultServices(Type type)
{
var serviceTypes = new List<Type>();
foreach (var interfaceType in type.GetTypeInfo().GetInterfaces())
{
var interfaceName = interfaceType.Name;
if (interfaceType.IsGenericType)
{
interfaceName = interfaceType.Name.Left(interfaceType.Name.IndexOf('`'));
}
// 查询到实现类的名称是否是移除I
if (interfaceName.StartsWith("I"))
{
interfaceName = interfaceName.Right(interfaceName.Length - 1);
}
// 查询到实现类的名称是否以接口名结尾
if (type.Name.EndsWith(interfaceName))
{
serviceTypes.Add(interfaceType);
}
}
return serviceTypes;
}
}