Update sharepoint list item in C# via graph api with error 400 bad request

Question

I have a column with "ScheduledTimeSlot" already created in the SharePoint list but somehow i can't seem to update this column.

Verified that itemId, access token is correct as i am able to create item with another method, just having issues with updating items.

When i use string addItemJsonString = "{\"ScheduledTimeSlot\":\"13XX17101310238\"}"; it works. But when i try the following method, it will give me bad request error 400. I'm pretty sure it's the format issue.

        var root = new
        {
            fields = new Dictionary<string, string>
        {
            { "ScheduledTimeSlot", scheduledTimeSlot },  //column to update
        }
        };
        string addItemJsonString = JsonConvert.SerializeObject(root);

Full method below

    public async Task UpdateSharePointListItem(string webApiUrl, string itemId, string scheduledTimeSlot, string accessToken)
    {
        Console.WriteLine(itemId);
        Console.WriteLine(scheduledTimeSlot);
        var root = new
        {
            fields = new Dictionary<string, string>
        {
            { "ScheduledTimeSlot", scheduledTimeSlot },  //column to update
        }
        };

        string addItemJsonString = JsonConvert.SerializeObject(root);
        Console.WriteLine(addItemJsonString);
        string requestUrl = config.ApiUrl + "v1.0/sites/" + config.SiteId + "/lists/" + config.ListId + "/items/" + itemId + "/fields";
        HttpRequestMessage message = new HttpRequestMessage(new HttpMethod("PATCH"), requestUrl);
        message.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
        message.Content = new StringContent(addItemJsonString, Encoding.UTF8, "application/json");
        HttpClient.DefaultRequestHeaders.TryAddWithoutValidation("Content-Type", "application/json; charset=utf-8");
        HttpResponseMessage response = await HttpClient.SendAsync(message);
        Console.WriteLine(response);
    }

I have also tried the solution here: How to PATCH data using System.Net.Http

score 0 · Accepted Answer · answered Sep 19 '21 at 01:44

Managed to figure out the format as shown below for update. Had to remove the fields bracket for update.

            var root = new
            {
                ScheduledTimeSlot = scheduledTimeSlot
            };
            string addItemJsonString = JsonConvert.SerializeObject(root);

Remember to use PATCH instead of POST when you are trying to update sharepoint list.

Update sharepoint list item in C# via graph api with error 400 bad request

1 Answers1