Update SharePoint List item using Rest API in C#

Question

I am writing an API in Web API 2.0 on C# to perform various Actions with SharePoint List items.

I have tried the following code to update the Status Column of a List item:

HttpWebRequest endpointRequest = (HttpWebRequest)HttpWebRequest.Create("https://site.sharepoint.com/sites/OverDuePos/_api/web/lists/GetByTitle('Overdue POs List')/items(45)");

endpointRequest.Accept = "application/json;odata=verbose";
endpointRequest.Method = "MERGE";
// endpointRequest.Headers.Add("X-HTTP-Method", "MERGE");
endpointRequest.Headers.Add("IF-MATCH", "*");
endpointRequest.Headers.Add("X-RequestDigest", null);

string stringData = "{'__metadata': { 'type': 'SP.Data.TestlistListItem' }, 'PO_x0020_Status': 'whatever'}";
endpointRequest.ContentLength = stringData.Length;

string result = string.Empty;
endpointRequest.Headers.Add("Authorization",
"Bearer " + "token");
StreamWriter writer = new StreamWriter(endpointRequest.GetRequestStream());
writer.Write(stringData);
writer.Flush();

WebResponse wresp = endpointRequest.GetResponse();
using (StreamReader sr = new StreamReader(wresp.GetResponseStream()))
{
    result = sr.ReadToEnd();
}

The code is throwing the following Error:

'The remote server returned an error: (500) Internal Server Error.'

Similarly I have to update various columns in Multiple Lists.

Also, I cannot Hardcode any user and Password in the code.

Can anyone Help me sorting this Out?

Answer 1

You can refer to the following code to call rest api in c#

string taskListUrlById = "{0}_api/web/lists/GetByTitle('tasks')/items(932)"; //932 is the ID of the item to update
string SiteUrl = "yoursite";
string url = string.Format(taskListUrlById, SiteUrl);
string content = "{ '__metadata': { 'type': 'SP.Data.TasksListItem' }, 'Status': 'Close'}";

var credential = new System.Net.NetworkCredential("username",
                                                  "Password",
                                                   "domain");
                
using (var handler = new HttpClientHandler() { Credentials = credential, UseProxy = false })
    {
      using (var client = new HttpClient(handler))
        {
          client.DefaultRequestHeaders.Accept.Clear();
          client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
          var request = new HttpRequestMessage(HttpMethod.Post, url);
          request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
          request.Headers.Add("X-RequestDigest", await GetRequestDigest());
          request.Headers.Add("X-HTTP-Method", "MERGE");
          request.Headers.Add("IF-MATCH", "*");
          HttpContent strContent = new StringContent(content);
          strContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");
          strContent.Headers.ContentType.Parameters.Add(new NameValueHeaderValue("odata", "verbose"));
          request.Content = strContent;
          var response = await client.SendAsync(request);
        }
    }