Unable to send post requests to REST through HTTPClient

Question

Quick question that I'm struggling to figure out.

I've got a REST Api up and running that works fine with Postman which I'm trying to figure out how to call with a Post-request from Xamarin Forms (using HTTPClient).

This is my current code:

    public CreateFoundation()
    {
        InitializeComponent();
        lblInstructions.FontAttributes = FontAttributes.Bold;
        lblInstructions.FontSize = Device.GetNamedSize(NamedSize.Medium, typeof(Label));

        btnCreate.Clicked += async (s, e) =>
            {
                var arb = await PostCreateFoundation(txtCreateFoundation.Text); 
                await DisplayAlert("Clicked", "I was clicked. Text was: " + arb, "OK");
            };
    }


    public async Task<string> PostCreateFoundation(string arbitrary)
    {

        Debug.WriteLine("I'm in!");
        var client = new System.Net.Http.HttpClient();
        client.DefaultRequestHeaders.Add("Accept", "application/json");
        var content = new StringContent(arbitrary); 

        var response = await client.PostAsync("http://myapi.com/RestfulAPI/api/Ole_foundations/Insert/", content);

        var result = (response.Content.ReadAsStringAsync().Result); 
        return result;


    }

When displaying the returned string ( arb ) I can see that the uri is http://myapi.com/RestfulAPI/api/Ole_foundations/Insert/. , regardless of what I send as the arbitrary string...

The resulting url when sending the string "test" is:

{MESSAGE": "No HTTP resource was found that matches the request URI ' http://myapi.com/RestfulAPI/api/Ole_foundations/Insert/ '."}

EDIT: The API takes an arbitrarily string as a token, adds a predefined object to the database and returns the passed in arbitrary string as a return token.

REST API function header:

    [HttpPost]
    public string Insert(string s)

Answer 1

When an action parameter is a simple type like a string, WebAPI assumes it should look for it in the query string. But you are passing it in the body. Try changing the method signature on the API side to:

public string Insert([FromBody]string s)

Answer 2

1. Remove the final "/" on the uri

   Should be:

   http://myapi.com/RestfulAPI/api/Ole_foundations/Insert

2. Also what Todd Meiner said