t4mvc:无法继承没有默认构造函数的控制器类? [英] t4mvc : Cannot inherit a controller class which has no default constructor?

问题描述

我在 MVC2 中使用 T4MVC.

I am using T4MVC with MVC2.

我有以下构建块:

1. 一个简单的实体接口，它定义了每个 POCO 实体必须有一个 long Id 属性:

public interface IEntity
{
    public long Id;
}

一个简单的 POCO 类，它实现了 IEntity 接口并具有一些字符串属性:

A simple POCO class which implements the IEntity interface and has some string properties:

public class CD : IEntity
{
    public long Id { get; set; }

    public long Name { get; set; }
}

基本控制器:

A base controller:

public abstract class EntityController<T> : Controller where T : class, global::IEntity
{
    public EntityController(IEntityManager<T> manager);
}

我在我的 CDController 中使用了这个基本控制器(其中 CDManager 实现了 IEntityManager 接口，这是一个要添加的 UnitOfWork 模式CRUD 功能):

I use this base controller in my CDController (where CDManager implements the IEntityManager interface, which is a UnitOfWork pattern to add CRUD functionality):

public partial class CDController : EntityController<CD>
{
    public CDController() : base(new CDManager()) { }
}

当我运行我的 t4 模板时，会生成以下代码:

When I run my t4 template, this code is generated:

namespace MyApp.Web.Controllers {
    public partial class CDController {
        [GeneratedCode("T4MVC", "2.0"), DebuggerNonUserCode]
        protected CDController(Dummy d) { }

但这在编译过程中给了我一个错误:

But this gives me an error during compilation:

MyApp.EntityController不包含采用 0 个参数的构造函数

MyApp.EntityController<CD> does not contain a constructor that takes 0 arguments

我该如何解决这个问题?

How can I solve this?

推荐答案

我希望控制器基类是抽象的，并且它的构造函数受保护和参数化.通过向引发 NotImplementedException 的 ControllerBase 添加一个空白构造函数来解决这个问题.

I wanted by controller base class to be abstract and it's constructor protected and parametrized. Got around this issue by adding a blank constructor to ControllerBase that throws a NotImplementedException.

感觉不太对，但它完成了工作.唯一的问题是，当与依赖注入结合使用时，会调用错误的构造函数 - 因为它会抛出异常，应用程序将失败.

Doesn't quite feel right but it gets the job done. Only issue is when combined with dependency injection the wrong constructor will be called - since it throws an exception the app will bum out.

代码:

public abstract class ControllerBase : Controller
{
    protected object AlwaysSupply { get; private set; }

    public ControllerBase()
    {
        throw new NotImplementedException();
    }

    public ControllerBase(object alwaysSupply)
    {
        AlwaysSupply = alwaysSupply;
    }
}

这将导致 T4MVC 生成可编译的代码.错误似乎是它总是试图为控制器类生成一个空白(无参数)构造函数.

This will cause T4MVC to generate compilable code. The fault seems to be it always tries to generate a blank (no parameters) constructor for controller classes.

希望这对某人有所帮助.

Hope this helps someone.

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