我遵循了本教程，该教程效果很好，直到我修改了我的教程DbContext以拥有其他构造函数。我现在在分辨率方面遇到问题，不确定如何解决此问题。有没有一种简单的方法可以强制它获取无参数的构造函数，或者我处理方法不正确？

DbContext 有两个构造函数：

public class DashboardDbContext : DbContext
{
    public DashboardDbContext() : base("DefaultConnection") { }

    public DashboardDbContext(DbConnection dbConnection, bool owns)
        : base(dbConnection, owns) { }
}

SiteController 构造函数：

private readonly IDashboardRepository _repo;

public SiteController(IDashboardRepository repo)
{
    _repo = repo;
}

仓库：

DashboardDbContext _context;

public DashboardRepository(DashboardDbContext context)
{
    _context = context;
}

UnityResolver 码：

public class UnityResolver : IDependencyResolver
{
    private readonly IUnityContainer _container;

    public UnityResolver(IUnityContainer container)
    {
        _container = container;
    }

    public object GetService(Type serviceType)
    {
        try
        {
            return _container.Resolve(serviceType);
        }
        catch (ResolutionFailedException)
        {
            return null;
        }
    }

    public IEnumerable<object> GetServices(Type serviceType)
    {
        try
        {
            return _container.ResolveAll(serviceType);
        }
        catch (ResolutionFailedException)
        {
            return new List<object>();
        }
    }

    public IDependencyScope BeginScope()
    {
        var child = _container.CreateChildContainer();
        return new UnityResolver(child);
    }

    public void Dispose()
    {
        _container.Dispose();
    }
}

WebApiConfig：

var container = new UnityContainer();
container.RegisterType<IDashboardRepository, DashboardRepository>(new HierarchicalLifetimeManager());
config.DependencyResolver = new UnityResolver(container);

WebApi呼叫发生错误：

System.InvalidOperationException：尝试创建“
SiteController”类型的控制器时发生错误。确保控制器具有无参数的公共构造函数。

at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType) 
at System.Web.Http.Controllers.HttpControllerDescriptor.CreateController(HttpRequestMessage request) 
at System.Web.Http.Dispatcher.HttpControllerDispatcher.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken) 
at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__0.MoveNext()

InnerException：System.ArgumentException：类型’Dashboard.Web.Controllers.SiteController’没有默认的构造函数。

at System.Linq.Expressions.Expression.New(Type type) 
at System.Web.Http.Internal.TypeActivator.Create[TBase](Type instanceType) 
at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.GetInstanceOrActivator(HttpRequestMessage request, Type controllerType, Func`1& activator) 
at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)

在添加第二个构造函数之前，该教程非常出色，并且一直对我有效。