t4mvc：不能继承一个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

我使用T4MVC与MVC2。

I am using T4MVC with MVC2.

我有以下构建块：

1. 一个简单的实体接口，它定义每个POCO实体必须具有 long Id 属性：

public interface IEntity
{
    public long Id;
}

一个简单的POCO类， 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);
}

CDController （其中 CDManager 实现 IEntityManager 接口，这是一个UnitOfWork模式添加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) { }

但是这在编译期间给我一个错误：

But this gives me an error during compilation:

MyApp.EntityController< CD>不包含带有0个参数的构造函数

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

我如何解决这个问题？

推荐答案

我想要的控制器基类是抽象的，它的构造函数保护和参数化。通过向ControllerBase添加一个空的构造函数来抛出NotImplementedException，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.

不太正确，但它完成了工作。只有当与依赖注入相结合时，错误的构造函数才会被调用 - 因为它抛出一个异常，应用程序将会消失。

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生成可编译代码。该错误似乎总是尝试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.

希望这有助于某人。

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