'TestController.Post()': not all code paths return a value

问题

I am returning HttpResponseMessage, but still my code complains and throw below error,

'TestController.Post()': not all code paths return a value

What to return here?

public async Task<IHttpActionResult> Post()
    {
        var response = await IsDataValid();
        if (response)
            return Ok(new HttpResponseMessage(HttpStatusCode.OK));
    }

回答1:

You need to add just few more line of code to deal with the above error.

public async Task<IHttpActionResult> Post()
{
    var response = await IsDataValid();
    if (response)
        return Ok(new HttpResponseMessage(HttpStatusCode.OK));
    else
        return NotFound();
}

The else part is important here.

回答2:

If within ApiController, no need to return HttpResponseMessage if returning IHttpActionResult. Use the controller's helper methods.

For example

public async Task<IHttpActionResult> Post() {
    var response = await IsDataValid();
    if (response)
        return Ok();

    return BadRequest();
}

来源：https://stackoverflow.com/questions/58926622/testcontroller-post-not-all-code-paths-return-a-value