Updating SharePoint 2013 List Title Using REST and HttpClient

Question

I am trying to update a SharePoint 2013 list title using the REST api and HttpClient. I have the following code but the StatusCode is returning BadRequest.

private async void UpdateTitle()
    {
        string webUrl = http://server;
        Uri uri = new Uri(webUrl + "/_api/web/lists/GetByTitle('Old')");
        //start replacement
        HttpClientHandler httpClientHandler = new HttpClientHandler();
        httpClientHandler.UseDefaultCredentials = true;
        HttpClient client = new HttpClient(httpClientHandler);
        client.DefaultRequestHeaders.Add("ContentType", "application/json;odata=verbose");
        string digest = await GetFormDigest("http://devsp13.dev.local/_api/contextinfo");
        client.DefaultRequestHeaders.Add("X-RequestDigest", digest);
        client.DefaultRequestHeaders.Add("X-HTTP-Method", "Merge");
        client.DefaultRequestHeaders.Add("IF-MATCH", "*");

        HttpContent content = new StringContent("{ '__metadata': { 'type': 'SP.List' }, 'Title': 'NewTitle' }");
        HttpResponseMessage response = await client.PostAsync(uri, content);
        response.EnsureSuccessStatusCode();}

I'm guessing I've missed something in forming the HttpClient but I'm struggling to see what. Any help is much appreciated.

Cheers,

Geoff

Answer 1

Try adding Accept to the HttpClient DefaultRequestHeaders and set the ContentType on the HttpContent Headers instead. This worked for me.

HttpClientHandler handler = new HttpClientHandler();
handler.UseDefaultCredentials = true;
HttpClient client = new HttpClient(handler);
client.DefaultRequestHeaders.Add("Accept", "application/json;odata=verbose");
client.DefaultRequestHeaders.Add("X-RequestDigest", GetFormDigest());
client.DefaultRequestHeaders.Add("X-HTTP-Method", "MERGE");
client.DefaultRequestHeaders.Add("IF-MATCH", "*");

HttpContent content = new StringContent(metadataString);
content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
content.Headers.ContentType.Parameters.Add(new NameValueHeaderValue("odata", "verbose"));
HttpResponseMessage response = await client.PostAsync(uri, content);
response.EnsureSuccessStatusCode();