asp.net-mvc – 使模型绑定适用于没有默认构造函数的模型

public class CompanyModelBinder: DefaultModelBinder
{
    private const string sessionKey = "CustomProfile";

    protected override object CreateModel(ControllerContext controllerContext,ModelBindingContext bindingContext,Type modelType)
    {
        if(modelType == typeOf(Company))
        {
            var customProfile = (CustomProfile) controllerContext.HttpContext.Session[sessionKey];
            // create the Cart if there wasn't one in the session data
            if (customProfile == null)
            {
                customProfile = new CustomProfile("default name");
                controllerContext.HttpContext.Session[sessionKey] = customProfile;
            }

            return new Company(customProfile);
        }
        else
        {
            //just in case this gets registered for any other type
            return base.CreateModel(controllerContext,bindingContext,modelType)
        }
    }
}

您只需将此绑定器注册到Company类型,方法是将其添加到global.asax Application_Start方法：

ModelBinders.Binders.Add(typeOf(Company),CompanyModelBinder);

另一种选择可能是通过继承DefaultModelBinder来使用Ninject依赖项创建依赖性感知模型绑定器(因为您使用的是Ninject,它知道如何构建具体类型的实例而无需注册它们).
但是,您需要配置一个在Ninject中构建CustomProfile的自定义方法,我相信您可以使用ToMethod().
为此您将提取您将在控制器工厂外提取Ninject内核的配置：

public static class NinjectBootStrapper{
    public static IKernel GetKernel()
    {
        IKernel  ninjectKernel = new StandardKernel();
        AddBindings(ninjectKernel);
    }

    private void AddBindings(IKernel ninjectKernel)
    {
        ninjectKernel.Bind<IAuthProvider>().To<FormsAuthProvider>();
        ninjectKernel.Bind<IMembershipProvider>().To<MembershipProvider>();
        ninjectKernel.Bind<ICustomProfileProvider>().To<CustomProfileProvider>();
        ninjectKernel.Bind<ICompanyProvider>().To<CompanyProvider>();
        ninjectKernel.Bind<CustomProfile>().ToMethod(context => /*try to get here the current session and the custom profile,or build a new instance */ );
    }
}

public class NinjectControllerFactory : DefaultControllerFactory
{
    private readonly IKernel ninjectKernel;

    public NinjectControllerFactory(IKernel kernel)
    {
        ninjectKernel = kernel;
    }

    protected override IController GetControllerInstance(RequestContext requestContext,Type controllerType)
    {
        return controllerType == null
                   ? null
                   : (IController) ninjectKernel.Get(controllerType);
    }
}

在这种情况下,您将创建此模型绑定器：

public class NinjectModelBinder: DefaultModelBinder
{
    private readonly IKernel ninjectKernel;

    public NinjectModelBinder(IKernel kernel)
    {
        ninjectKernel = kernel;
    }

    protected override object CreateModel(ControllerContext controllerContext,Type modelType)
    {
        return ninjectKernel.Get(modelType) ?? base.CreateModel(controllerContext,modelType)
    }
}

你会将global.asax更新为：

IKernel kernel = NinjectBootStrapper.GetKernel();
ControllerBuilder.Current.SetControllerFactory(new NinjectControllerFactory(kernel));
ModelBinders.Binders.DefaultBinder = new NinjectModelBinder(kernel);