SharePoint 2016:获取访问令牌

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;
using Newtonsoft.Json;

public class TokenResponse
{
    public string access_token { get; set; }
    public string token_type { get; set; }
    public int expires_in { get; set; }
}

public class SharePointTokenHelper
{
    private const string TokenEndpoint = "https://your-sharepoint-site/_layouts/15/OAuthAuthorize.aspx";
    private const string ClientId = "your-client-id";
    private const string ClientSecret = "your-client-secret";

    public async Task<string> GetAccessTokenAsync(string authorizationCode)
    {
        using (var client = new HttpClient())
        {
            var content = new FormUrlEncodedContent(new[]
            {
                new KeyValuePair<string, string>("grant_type", "authorization_code"),
                new KeyValuePair<string, string>("code", authorizationCode),
                new KeyValuePair<string, string>("client_id", ClientId),
                new KeyValuePair<string, string>("client_secret", ClientSecret),
                new KeyValuePair<string, string>("redirect_uri", "https://your-app.com/callback")
            });

            var response = await client.PostAsync(TokenEndpoint, content);
            response.EnsureSuccessStatusCode();

            var tokenResponse = JsonConvert.DeserializeObject<TokenResponse>(await response.Content.ReadAsStringAsync());
            return tokenResponse.access_token;
        }
    }
}