如何在asp.net mvc中使用ms graph api更改AD B2C用户密码

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;
using Microsoft.Identity.Client;

public class PasswordChangeService
{
    private readonly string _tenantId;
    private readonly string _clientId;
    private readonly string _clientSecret;
    private readonly string _graphEndpoint = "https://graph.microsoft.com/v1.0";

    public PasswordChangeService(string tenantId, string clientId, string clientSecret)
    {
        _tenantId = tenantId;
        _clientId = clientId;
        _clientSecret = clientSecret;
    }

    public async Task ChangePasswordAsync(string userId, string newPassword)
    {
        var app = ConfidentialClientApplicationBuilder.Create(_clientId)
            .WithClientSecret(_clientSecret)
            .WithAuthority(new Uri($"https://login.microsoftonline.com/{_tenantId}"))
            .Build();

        var result = await app.AcquireTokenForClient(new[] { "https://graph.microsoft.com/.default" }).ExecuteAsync();
        var accessToken = result.AccessToken;

        using (var httpClient = new HttpClient())
        {
            httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
            var requestContent = new StringContent($"{{\"password\": \"{newPassword}\"}}");
            requestContent.Headers.ContentType = MediaTypeHeaderValue.Parse("application/json");

            var response = await httpClient.PatchAsync($"{_graphEndpoint}/users/{userId}", requestContent);

            if (response.IsSuccessStatusCode)
            {
                Console.WriteLine("Password changed successfully.");
            }
            else
            {
                Console.WriteLine($"Failed to change password: {response.ReasonPhrase}");
            }
        }
    }
}