All sample provided in this topic were created with the Screen-Based API Wrapper. If you want your client application to not depend on the UI changes in the Acumatica ERP application, you should use the screen-based API wrapper, which is described in Acumatica ERP Documentation

To communicate with the REST Contract-Based API of Acumatica ERP your client application must always perform the following 3 steps:

1. log into Acumatica ERP instance and get cookie with user session information

2. interact with one of Contract-Based API endpoints available on Acumatica ERP instance

3. log out from Acumatica ERP to close user session

All samples provided in this topic were built with the Default endpoint, always deployed as part of the standard Acumatica ERP installation process. On the Web Service Endpoints screen (SM.20.70.60) you can view the details of existing endpoints or configure your custom endpoints of the Acumatica ERP contract-based web services:

For your reference, below is implementation of the RestService class used in all samples above to interact with the Contract-Based web service of Acumatica ERP:

public class RestService : IDisposable
{
    private readonly HttpClient _httpClient;
    private readonly string _acumaticaBaseUrl;
    private readonly string _acumaticaEndpointUrl;

    public RestService(string acumaticaBaseUrl, string endpoint,
        string userName, string password,
        string company, string branch)
    {
        _acumaticaBaseUrl = acumaticaBaseUrl;
        _acumaticaEndpointUrl = _acumaticaBaseUrl + "/entity/" + endpoint + "/";
        _httpClient = new HttpClient(
            new HttpClientHandler
            {
                UseCookies = true,
                CookieContainer = new CookieContainer()
            })
        {
            BaseAddress = new Uri(_acumaticaEndpointUrl),
            DefaultRequestHeaders =
            {
                Accept = {MediaTypeWithQualityHeaderValue.Parse("text/json")}
            }
        };

        var str = new StringContent(
            new JavaScriptSerializer()
                .Serialize(
                    new
                    {
                        name = userName,
                        password = password,
                        company = company,
                        branch = branch
                    }),
                    Encoding.UTF8, "application/json");

        _httpClient.PostAsync(acumaticaBaseUrl + "/entity/auth/login", str)
            .Result.EnsureSuccessStatusCode();
    }

    void IDisposable.Dispose()
    {
        _httpClient.PostAsync(_acumaticaBaseUrl + "/entity/auth/logout",
            new ByteArrayContent(new byte[0])).Wait();
        _httpClient.Dispose();
    }

    public string GetList(string entityName)
    {
        var res = _httpClient.GetAsync(_acumaticaEndpointUrl + entityName)
            .Result.EnsureSuccessStatusCode();

        return res.Content.ReadAsStringAsync().Result;
    }

    public string GetList(string entityName, string parameters)
    {
        var res = _httpClient.GetAsync(_acumaticaEndpointUrl + entityName + "?" + parameters)
            .Result.EnsureSuccessStatusCode();

        return res.Content.ReadAsStringAsync().Result;
    }
}

In all samples above, you made changes to both the _AllowedValues and _AllowedLabels arrays. If your task is to modify only label (external value) of a drop-down item, consider using Translation Dictionaries. For more information on Translation Dictionaries see Acumatica ERP Documentation

The code snippet above was created using the Json.NET framework (Newtonsoft.Json.dll).

To obtain HTTP cookie header from a SOAP response, add a reference to the .Net framework System.ServiceModel and System.ServiceModel.Web assemblies and the following 2 using directives in your code file:

using System.ServiceModel;
using System.ServiceModel.Web;