从BaseController继承的自定义控制器中的null ControllerContext [英] Null ControllerContext in my custom controller inheriting from BaseController

问题描述

我建立了自己的Controller类，该类继承自BaseController.但是，构造函数中的ControllerContext为"null".我应该在哪里指定ControllerContext?

I built my own Controller class which inherits from BaseController. However the ControllerContext in constructor is "null". Where should I specify the ControllerContext?

推荐答案

在继承层次结构中的任何基本构造函数中均未分配ControllerContext属性.控制器是由控制器工厂创建的，并在没有分配ControllerContext属性的情况下传递回去.

The ControllerContext property is not assigned to in any of the base constructors in your inheritance hierachy. A controller is created by a controller factory and passed back without the ControllerContext property being assigned to.

使用Reflector，我们可以查看分配发生的位置:

Using Reflector, we can look at where the assignment takes place:

protected virtual void Initialize(RequestContext requestContext)
{
    this.ControllerContext = new ControllerContext(requestContext, this);
}

Initialize方法是从虚拟Execute方法调用中调用的:

The Initialize method is invoked from the virtual Execute method call:

protected virtual void Execute(RequestContext requestContext)
{
    if (requestContext == null)
    {
        throw new ArgumentNullException("requestContext");
    }
    this.VerifyExecuteCalledOnce();
    this.Initialize(requestContext);
    this.ExecuteCore();
}

这意味着可以访问ControllerContext属性的最早时间是通过覆盖Execute或Initialize方法(但首先调用base.Execute或base.Initialize):

This means the earliest point at which you can access the ControllerContext property is by overriding the Execute or Initialize method (but calling base.Execute or base.Initialize first):

protected override void Execute(RequestContext requestContext)
{
  base.Execute(requestContext);

  // .ControllerContext is available from this point forward.
}

protected override void Initialize(RequestContext requestContext)
{
  base.Initialize(requestContext);

  // .ControllerContext is available from this point forward.
}

后一个(Initialize)是可以使用ControllerContext属性的绝对最早点，除非您自己处理分配，否则不建议这样做(因为框架的某些部分取决于将那个属性分配给当时).

The latter (Initialize) is the absolute earliest point at which you can use the ControllerContext property, unless you handled the assignment yourself, which is not recommended (as parts of the framework will be dependent on having that property assigned to at that time).

希望有帮助.

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