如何在自定义ValidationAttribute中访问存储库？

Question

public class UniqueNameAttribute : ValidationAttribute
{
    private const string UniqueNameViolationMessage = "This name is already taken. Please select another.";

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        //return somerepo.IsUniqueName(name)
        //how do I get access to repo here?  Tried DI with autofac but it came out as null
    }
}

我正在使用依赖注入将存储库注入我的Web API.但是,似乎我无法注入ValidationAttribute.如果我尝试注入,它会出现null.我正在使用Autofac进行DI.有没有其他方式可以访问我的回购？

请注意,我只使用Web API,而不是MVC,所以我不能使用MVC DependencyResolver.

builder.RegisterType<MyRepository>().As<IMyRepository>().InstancePerRequest();

var container = builder.Build();
GlobalConfiguration.Configuration.DependencyResolver = new AutofacWebApiDependencyResolver((IContainer)container); ;

Answer 1

我猜你错过了这一行：

var builder = new ContainerBuilder();
builder.RegisterWebApiFilterProvider(config);
var container = builder.Build();

并且不是继承自IActionFilter，而是继承自IAutofacActionFilter。

更多详细信息请参见：https://autofaccn.readthedocs.io/en/latest/integration/webapi.html#provide-filters-via-dependency-injection