背景
- 有一些特殊需求，需要像StringBoot那样使用属性注入。(不推荐使用属性注入)
实现
- 设计一个属性注入注解:
InjectAttribute
[AttributeUsage(AttributeTargets.Property)]
public class InjectAttribute : Attribute
{}
- 设计属性注入服务接口:
IResolvedService
public interface IResolvedService<TService> where TService : class
{TService Service { get; }
}
- 实现属性注入服务
internal class ServiceResolver<TService> : IResolvedService<TService> where TService : class
{private static readonly ConcurrentDictionary<Type, PropertyInfo[]> _propertyCache = new();public ServiceResolver(IServiceProvider serviceProvider){Service = ResolveService(serviceProvider);}public TService Service { get; }private static void InjectProperties(IServiceProvider services, object instance){ArgumentNullException.ThrowIfNull(instance);var properties = _propertyCache.GetOrAdd(instance.GetType(), type =>type.GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic).Where(prop => prop.CanWrite && Attribute.IsDefined(prop, typeof(InjectAttribute))).ToArray());foreach (var property in properties){var dependency = services.GetService(property.PropertyType)?? throw new InvalidOperationException($"Failed to resolve dependency for property '{property.Name}' of type '{property.PropertyType.FullName}'.");property.SetValue(instance, dependency);}}private static TService ResolveService(IServiceProvider services){var service = services.GetService(typeof(TService));if (service is not TService typedService){throw new InvalidOperationException($"Unable to resolve service of type '{typeof(TService).FullName}'.");}InjectProperties(services, typedService);return typedService;}
}
- 在DI中注册服务
services.AddTransit(typeof(IResolvedService<>),typeof(ResolvedService<>));
- 定义属性注入
public class ExampleService
{[Inject] DependencyService Dependency { get; set; }
}
- 使用服务
- 使用构造注入
public class SomeViewModel
{private readonly ExampleService _exampleService;public SomeViewModel(IResolvedService<ExampleService> exampleService){_exampleService = exampleService.Service;}
}
- 使用ServiceProvider获取服务
IResolvedService resolver = serviceProvider.GetRequiredService<IResolvedService<ExampleService>();
ExampleService service = resolver.Service;
最后
spring官方也不推荐属性注入，微软没有支持这个也是正常的。这里给有需要的兄弟提供一下思路。