CS:0021 Error code in Azure Function project in VS for running Microsoft Graph API with Azure Functions

Question

I am following this tutorial on how to run Microsoft Graph API with Azure funtion:

Azure Function Tutorial

I have followed the instructions clearly and insert this code in my project:

using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using System.Security.Claims;
using Azure.Identity;
using Microsoft.Graph;

namespace AZFunction1
{
    public static class Function1
    {

        [FunctionName("Function1")]
        public static async Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
        ILogger log, ClaimsPrincipal claimIdentity)
        {

            var options = new TokenCredentialOptions
            {
                AuthorityHost = AzureAuthorityHosts.AzurePublicCloud
            };


            var clientSecretCredential = new ClientSecretCredential(
                Constants.TenantId, Constants.AppId, Constants.ClientSecret, options);

            var graphClient = new GraphServiceClient(clientSecretCredential, Constants.scopes);
            var user = await graphClient.Users[claimIdentity.Identity.Name].GetAsync();
            var json = Newtonsoft.Json.JsonConvert.SerializeObject(user);
            return new OkObjectResult(json);

        }
    }
}

However, I am getting this error on this code: graphClient.Users[claimIdentity.Identity.Name]

CS0021: Cannot apply indexing with [] to an expression of type 'Object'

Can someone please help me?

Any help will be much appreciated.

I tried using ChatGPT which suggest for me to use the following code but error stays the same:

using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using System.Security.Claims;
using Azure.Identity;
using Microsoft.Graph;

namespace AZFunction1
{
    public static class Function1
    {
        [FunctionName("Function1")]
        public static async Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
        ILogger log, ClaimsPrincipal claimIdentity)
        {
            var options = new TokenCredentialOptions
            {
                AuthorityHost = AzureAuthorityHosts.AzurePublicCloud
            };

            var clientSecretCredential = new ClientSecretCredential(
                Constants.TenantId, Constants.AppId, Constants.ClientSecret, options);

            var graphClient = new GraphServiceClient(clientSecretCredential, Constants.scopes);

            // Extract user ID from ClaimsPrincipal
            var userId = claimIdentity?.FindFirst(ClaimTypes.NameIdentifier)?.Value;

            // Log the user ID
            log.LogInformation($"User ID: {userId}");

            if (string.IsNullOrEmpty(userId))
            {
                log.LogError("User identifier is null or empty.");
                return new BadRequestObjectResult("Invalid user identifier.");
            }

            try
            {
                var user = await graphClient.Users[userId].Request().GetAsync();
                var json = JsonConvert.SerializeObject(user);
                return new OkObjectResult(json);
            }
            catch (ServiceException ex)
            {
                log.LogError($"Error fetching user: {ex.Message}");
                return new StatusCodeResult(StatusCodes.Status500InternalServerError);
            }
        }
    }
}

Answer 1

Your code is correct and it works for me without any error.

• Make sure if your using latest stable packages.

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
    <RootNamespace>_78686917</RootNamespace>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Azure.Identity" Version="1.12.0" />
    <PackageReference Include="Microsoft.Graph" Version="5.56.0" />
    <PackageReference Include="Microsoft.NET.Sdk.Functions" Version="4.4.0" />
  </ItemGroup>
  <ItemGroup>
    <None Update="host.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update="local.settings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
      <CopyToPublishDirectory>Never</CopyToPublishDirectory>
    </None>
  </ItemGroup>
</Project>

• I am using same code alike you.

using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Azure.Identity;
using Microsoft.Graph;
using System.Security.Claims;
using Newtonsoft.Json;

namespace _78686917
{
    public static class Function1
    {
        [FunctionName("Function1")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
            ILogger log, ClaimsPrincipal claimIdentity)
        {
            var options = new TokenCredentialOptions
            {
                AuthorityHost = AzureAuthorityHosts.AzurePublicCloud
            };


            var clientSecretCredential = new ClientSecretCredential(
                Constants.TenantId, Constants.AppId, Constants.ClientSecret, options);

            var graphClient = new GraphServiceClient(clientSecretCredential, Constants.scopes);
            var user = await graphClient.Users[claimIdentity.Identity.Name].GetAsync();
            var json = JsonConvert.SerializeObject(user);
            return new OkObjectResult(json);
        }
    }
}

• I have a constants class as shown below.

namespace _78686917
{
    public class Constants
    {
        public static string AppId = "52cb***818";
        public static string TenantId = "27****b0b";
        public static string ClientSecret = "oN~******Javy";
        public static string TenantName = "<tenantName>";
        public static string[] scopes = new[] { "https://graph.microsoft.com/.default" };

    }
}

• I have added below permissions in the registered app.

I am getting expected response both in local as well as in function app. Please ensure if you are using latest version of core tools.