Error CS0029 Cannot implicitly convert type 'Microsoft.AspNetCore.Mvc.ActionResult' to 'System.Collections.Generic.List<>'

Question

I tried the solutions posted on StackOverflow, but none of them worked. I have a method calling a web service. The code is as following and I keep getting a compiler error:

    public async Task<ActionResult <List<items>>>getitems()
    {
        HttpClient client = new HttpClient();
        client.BaseAddress = new Uri("https://localhost:5001/");
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(
        new MediaTypeWithQualityHeaderValue("application/json"));
        var Res = await client.PostAsJsonAsync("api/sub", ids);
        Res.EnsureSuccessStatusCode();
        if (Res.IsSuccessStatusCode)
        {
            var Response = Res.Content.ReadAsStringAsync().Result;   
            var sub = JsonConvert.DeserializeObject<JArray>(Response);
            List<items> item = sub.ToObject<List<items>>();
            return Ok(item);
        }
    }

Then I call the method from a different class as following:

    public async Task<List<items>> getService(List<string> ids)
    {
        var IdentificationIdsToOrder = new JObject();
        foreach (var id in ids)
        {
            var newId = new JProperty("ids", id);
            IdentificationIdsToOrder.Add(newId);
        }
        _controller = new getitems();
        var Res = await _controller.getitems();         
        var ItemList = Res.Result;
        return ItemList;
    }
}

Here it goes wrong with the return value and I can't compile.

What I'm missing?

There are inconsistencies with the code shown. Provide a minimal reproducible example that clarifies your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. — Nkosi
– Nkosi, Commented Mar 10, 2019 at 0:21
@Nkosi sorry, I was trying different apporches and mixed some code together, following different examples from Stack overflow — dolly_do
– dolly_do, Commented Mar 10, 2019 at 0:37
This is understood. But in order to get help you need to have a least a base set of code that we can use to reproduce your problem and find a solution. — Nkosi
– Nkosi, Commented Mar 10, 2019 at 0:38
Yes, I edited the post method. which is actually working when I tested with postman. but the issue is that I can't get to work when I call it from a different class — dolly_do
– dolly_do, Commented Mar 10, 2019 at 0:41
ActionResult is used with Mvc to return response when the action method is called. I would extract your api calling code into another class that simply returns the List<> and then use that in the getitems action and in your getService method. — Eugene S.
– Eugene S., Commented Mar 10, 2019 at 0:58

Fyodor Yemelyanenko · Accepted Answer · 2019-03-10 07:39:35Z

1

In getService method you should use var ItemList = Res.Value; in place of var ItemList = Res.Result;

public async Task<List<items>> getService(List<string> ids)
{
    var IdentificationIdsToOrder = new JObject();
    foreach (var id in ids)
    {
        var newId = new JProperty("ids", id);
        IdentificationIdsToOrder.Add(newId);
    }

    _controller = new getitems();
    var Res = await _controller.getitems();         
    var ItemList = Res.Value;
    return ItemList;

}

answered Mar 10, 2019 at 7:39

Fyodor Yemelyanenko

11.9k2 gold badges33 silver badges41 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

dolly_do Over a year ago

this worked only after I removed the action result from the method I'm calling. That is why I up-voted Eugene S. comment

Collectives™ on Stack Overflow

Error CS0029 Cannot implicitly convert type 'Microsoft.AspNetCore.Mvc.ActionResult' to 'System.Collections.Generic.List<>'

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related