Sharepoint and REST - WebClient - Insert Data to list

Problem Definition

Add attachment to SharePoint list item using REST API and WebClient.

Prerequisites

In order to effectively deal with the data in the SharePoint List I will recommend using Newtonsoft.JSON that makes dealing with List data a lot easier.

In order to get JSON plugin go to NuGet and search for JSON.NET or NEWTONSOFT

SharePointAndRest_WebClient.cs

class dealing with SharePoint Data posting:

Code Help

/// <summary>
    /// Implement Sharepoint Functionality using WebClient
    /// </summary>
    public class SharePointAndRest_WebClient : IDisposable
    {
        private readonly WebClient webClient;
        public Uri WebUri { get; private set; }

        /// <summary>
        /// Intialize webclient and set it up for use with sharepoint using Default Credentials
        /// </summary>
        /// <param name="webUri">Basic url to sharepoint site</param>
        public SharePointAndRest_WebClient(Uri webUri)
        {
            webClient = new WebClient();
            webClient.Headers.Add("X-FORMS_BASED_AUTH_ACCEPTED", "f");
            webClient.Headers.Add(HttpRequestHeader.ContentType, "application/json;odata=verbose");
            webClient.Headers.Add(HttpRequestHeader.Accept, "application/json;odata=verbose");
            webClient.Headers.Add(HttpRequestHeader.UserAgent, "Mozilla/4.0+(compatible;+MSIE+5.01;+Windows+NT+5.0");
            webClient.UseDefaultCredentials = true;
            WebUri = webUri;
        }

        /// <summary>
        /// Inserts item in the list
        /// </summary>
        /// <param name="listTitle">Title of the List</param>
        /// <param name="payload">Data to store in the form of Annoymour method </param>
        public void InsertItem(string listTitle, object payload)
        {
            var formDigestValue = GetFormDigest();
            webClient.Headers.Add("X-RequestDigest", formDigestValue);
            var endpointUri = new Uri(WebUri, string.Format("_api/web/lists/getbytitle('{0}')/items", listTitle));
            var payloadString = JsonConvert.SerializeObject(payload);
            webClient.Headers.Add(HttpRequestHeader.ContentType, "application/json;odata=verbose");
            webClient.UploadString(endpointUri, "POST", payloadString);
        }

        /// <summary>
        /// Provides form data digest
        /// </summary>
        /// <returns></returns>
        private string GetFormDigest()
        {
            var endpointUri = new Uri(WebUri, "_api/contextinfo");
            var result = webClient.UploadString(endpointUri, "POST");
            JToken t = JToken.Parse(result);
            return t["d"]["GetContextWebInformation"]["FormDigestValue"].ToString();
        }

        /// <summary>
        /// IDisposable Implementation
        /// </summary>
        public void Dispose()
        {
            webClient.Dispose();
            GC.SuppressFinalize(this);
            GC.Collect();
        }
    }

SharePointAndRest.cs

Method calling SharePointAndRest_WebClient Class:

Code Help

        /// <summary>
        /// This method supplied the data and calls the execution of Insert
        /// </summary>
        public static void SharepointAndRest_WebClient_Insert()
        {
            //var webUri = new Uri(@"http://<your server>/<site>/");

            using (var client = new SharePointAndRest_WebClient(webUri))
            {
                var testEntry = new
                {
                    __metadata = new { type = "SP.Data.MessageTestListItem" },
                    Title = "TestEntry",
                    FirstName = "Byte",
                    LastName = "Rodeo",
                    EmailAddress = "test_test1234.com",
                    PhoneNumber = "(123) 456-7890",
                    AlternatePhoneNumber = "(234) 467-8901"
                };
                //client.InsertItem("MessageTest", testEntry);
            }
        }

Result

Also Look at

Sharepoint and REST - WebClient - Get List Data
Sharepoint and REST - WebClient - Update Data to List
Sharepoint and REST - WebClient - Delete Data from List