C# WebAPI未通过传递参数在控制器上找到任何操作

HomeController.cs

 class HomeController : ApiController
    {
        [HttpGet]
        public IHttpActionResult GetData(string name)
        {
            if (string.IsNullOrWhiteSpace(name))
            {
                throw new ArgumentNullException("username can not be empty");
            }
            return Ok("Test Done");
        }
    }

public void Configuration(IAppBuilder appBuilder)
        {           
            HttpConfiguration config = new HttpConfiguration();
            config.MapHttpAttributeRoutes();


            config.Routes.MapHttpRoute(
              name: "GetData",
              routeTemplate: "V2/{controller}/{name}",
              defaults: new { controller = "Home", action = "GetData" }
              );

            appBuilder.UseWebApi(config);
        }

StartUp.cs

 class HomeController : ApiController
    {
        [HttpGet]
        public IHttpActionResult GetData(string name)
        {
            if (string.IsNullOrWhiteSpace(name))
            {
                throw new ArgumentNullException("username can not be empty");
            }
            return Ok("Test Done");
        }
    }

public void Configuration(IAppBuilder appBuilder)
        {           
            HttpConfiguration config = new HttpConfiguration();
            config.MapHttpAttributeRoutes();


            config.Routes.MapHttpRoute(
              name: "GetData",
              routeTemplate: "V2/{controller}/{name}",
              defaults: new { controller = "Home", action = "GetData" }
              );

            appBuilder.UseWebApi(config);
        }

获取错误：

{
  "Message": "No HTTP resource was found that matches the request URI 'http://localhost:4057/V2/Home/GetData/'.",
  "MessageDetail": "No type was found that matches the controller named 'Home'."

[RoutePrefix("V2/Home")]
public class HomeController : ApiController
{
    [HttpGet]
    [Route("{name}", Name = "GetData")]
    public IHttpActionResult GetData(string name)
    {
        if (string.IsNullOrWhiteSpace(name))
        {
            throw new ArgumentNullException("username can not be empty");
        }
        return Ok("Test Done");
    }
}

public void Configuration(IAppBuilder appBuilder)
{
    HttpConfiguration config = new HttpConfiguration();
    config.MapHttpAttributeRoutes();
    appBuilder.UseWebApi(config);
}

---

尝试将方法名称更改为

Get

（有关详细信息）

---

如果您不想更改方法名称（），设置属性路由可能会有所帮助。

这里的问题很简单。 类的访问修饰符非常严格

 class HomeController : ApiController
    {

默认的访问修饰符是内部的，这意味着它不能公开访问

尝试将访问修饰符更改为

public

以公开服务

public class HomeController : ApiController
        {

我可以使用postman和我现有的web API复制您的问题

我的邮递员的错误：

因为，API控制器必须是公共的。但是，考虑在常规路由上使用属性路由，因为它更容易出错：

HomeController.cs:

{
  "Message": "No HTTP resource was found that matches the request URI 'http://localhost:4057/V2/Home/GetData/'.",
  "MessageDetail": "No type was found that matches the controller named 'Home'."

[RoutePrefix("V2/Home")]
public class HomeController : ApiController
{
    [HttpGet]
    [Route("{name}", Name = "GetData")]
    public IHttpActionResult GetData(string name)
    {
        if (string.IsNullOrWhiteSpace(name))
        {
            throw new ArgumentNullException("username can not be empty");
        }
        return Ok("Test Done");
    }
}

public void Configuration(IAppBuilder appBuilder)
{
    HttpConfiguration config = new HttpConfiguration();
    config.MapHttpAttributeRoutes();
    appBuilder.UseWebApi(config);
}

Startup.cs:

{
  "Message": "No HTTP resource was found that matches the request URI 'http://localhost:4057/V2/Home/GetData/'.",
  "MessageDetail": "No type was found that matches the controller named 'Home'."

[RoutePrefix("V2/Home")]
public class HomeController : ApiController
{
    [HttpGet]
    [Route("{name}", Name = "GetData")]
    public IHttpActionResult GetData(string name)
    {
        if (string.IsNullOrWhiteSpace(name))
        {
            throw new ArgumentNullException("username can not be empty");
        }
        return Ok("Test Done");
    }
}

public void Configuration(IAppBuilder appBuilder)
{
    HttpConfiguration config = new HttpConfiguration();
    config.MapHttpAttributeRoutes();
    appBuilder.UseWebApi(config);
}

---

[Routing]

属性

可能会有所帮助。方法的

名称

不是这里的问题。由于他使用的是

[HttpGet]

，因此不会有任何问题。另外，路由注释仅在特定版本的MVC中可用，我认为它是在MVC 5中引入的，它是在WebAPI 2中引入的。@codran Yes，他之所以使用它，是因为他的代码中出现了

IHttpActionResult

，对吗？@MartinBrandl确实给出了它，就像

config.maphttpAttribute路由的用户一样：）