Web Api oData v4 $ref 404 or server error

问题

Problem

I am able to successfully GET the related items from either end of this relationship using the following:

• http://localhost/api/Exercises(1)?$expand=Measurements
• http://localhost:49540/api/Exercises(1)/Measurements

Now I am trying to manage the relationship between them. There are a few examples Ive found out there that Ive tried and none work. Heres one and heres another.

Models

public class Exercise
{
    public int Id { get; set; }
    public virtual ICollection<Measurement> Measurements { get; set; }
}

public class Measurement
{
    public int Id { get; set; }
    public virtual ICollection<Exercise> Exercises { get; set; }
}

Actions

Here are the actions I have tried and their requests:

[HttpDelete]
public IHttpActionResult DeleteRef([FromODataUri] int key, [FromODataUri] string relatedKey, string navigationProperty)
{
   return StatusCode(HttpStatusCode.NoContent);
}

URL: http://localhost/api/Exercises(1)/Measurements$id=http://localhost/api/Measurements(4)

Result: 404

[HttpDelete]
[ODataRoute("Exercises({key})/Measurements({relatedKey})/$ref")]
public IHttpActionResult DeleteMeasurementFromExercise(int key, int relatedKey)
{
   return StatusCode(HttpStatusCode.NoContent);
    }

URL: n/a

Result: Server error: The path template 'Exercises({key})/Measurements({relatedKey})/$ref' on the action 'DeleteMeasurementFromExercise' in controller 'Exercises' is not a valid OData path template. The URI segment '$ref' is invalid after the segment 'Measurements({relatedKey})'.

Related

This guy had the same symptoms and was able to resolve it after Microsoft released a fix. I am running with the latest versions of Web API and oData and still have this problem.

<package id="Microsoft.AspNet.WebApi" version="5.2.3" targetFramework="net46" />
<package id="Microsoft.AspNet.OData" version="5.9.0" targetFramework="net46" />
<package id="Microsoft.OData.Core" version="6.15.0" targetFramework="net46" />
<package id="Microsoft.OData.Edm" version="6.15.0" targetFramework="net46" />

回答1:

As usual, minutes after posting a question to SO, the answer to the problem Im stuck on for days comes to me.

According to the Deleting a Relationship Between Entities at the bottom of this documentation, my URL should look like this:

DELETE http://host/Suppliers(1)/Products/$ref?$id=http://host/Products(1)

for an action like this:

public IHttpActionResult DeleteRef([FromODataUri] int key, [FromODataUri] string relatedKey, string navigationProperty)
{
    return StatusCode(HttpStatusCode.NoContent);
}

The documentation is wrong. After some digging, I found your url should look like this:

DELETE http://host/Suppliers(1)/Products(2)/$ref

来源：https://stackoverflow.com/questions/36678752/web-api-odata-v4-ref-404-or-server-error