使用端点路由和 MVC 时，如何从 Endpoint.RequestDelegate 获取 IActionContextAccessor？

Question

I've got a asp .net core 3.1 application and have configured MVC and Endpoint Routing. Assume I have an Endpoint object (it won't always be the Endpoint associated with the current request), I then have it's RequestDelegate. I'd like to get the IActionContextAccessor from this RequestDelegate. In the following example, when I'm in debug mode I can see the _actionContextAccessor so I know it's there.

var endpoint = this.httpContextAccessor.HttpContext.GetEndpoint();

I'm sure you'd like more context of what I'm doing and I can give you more if you like but the gist of this question is to assume I have an Endpoint object and I'm configured to use MVC, how can I get the IActionContextAccessor?

UPDATE

What I'm ultimately trying to get is the actions parameters. Just the type of the input parameters. We follow a one input model convention so actually what I want is that one input model's type.

Answer 1

To determine the type of an action's parameters, there's no need to use IActionContextAccessor or the ActionContext property it exposes. An Endpoint instance contains a set of metadata: for an endpoint that represents an action, this contains an instance of ActionDescriptor , which, unsurprisingly, describes an action. One of its properties is Parameters , which exposes the set of parameters for that action.

Putting that all together, here's an example of how to get to the type of a single action parameter, as requested:

var actionDescriptor = endpoint.Metadata.GetMetadata<ActionDescriptor>();

if (actionDescriptor != null)
{
    var actionParameterType = actionDescriptor.Parameters.SingleOrDefault()?.ParameterType;

    // ...
}