IoT Hub Device Provisioning Service - Device Registration Status Lookup API C# Code Sample Required

Hello,

Can anyone point me to a C# code sample in how to use the "Runtime Registration - Device Registration Status Lookup" API by implementing the code through C#?

The MS docs does not give any helpful information in how to use the service unless without doing it through an HTTP REST call using something like postman. https://zcusa.951200.xyz/en-us/rest/api/iot-dps/device/runtime-registration/device-registration-status-lookup

I'm expecting to find an example that uses the C# HTTP Client class.

My use case is based on completion of the IOT device provisioning service with TPM. https://zcusa.951200.xyz/en-us/azure/iot-dps/quick-create-simulated-device-tpm?pivots=programming-language-ansi-c

Once registered the first time, on the next reboot I want to check the registration status before re-provisioning unnecessarily each time. I was hoping that the Microsoft.Azure.Devices.Provisioning.Client SDK might provide a C# alternative to using the Status Lookup API, or at least provide a code sample somewhere in how to use the service through C#.

I've tried to implement a C# Http Client call using my code sample below, but I always get a StatusCode: 401, ReasonPhrase: 'Unauthorized' returned.

public class RequestBody  
{  
	[JsonPropertyName("payload")]  
	public string? Payload { get; set; }  
  
	[JsonPropertyName("registrationId")]  
	public string? RegistrationId { get; set; }  
  
	[JsonPropertyName("tpm")]  
	public Tpm? Tpm { get; set; }  
}  
  
public class Tpm  
{  
	[JsonPropertyName("endorsementKey")]  
	public string? EndorsementKey { get; set; }  
  
	[JsonPropertyName("storageRootKey")]  
	public string? StorageRootKey { get; set; }  
}  
  
private async Task CallWebApiWithPostRequest(string deviceId)  
{  
	Console.WriteLine("Initializing security using the local TPM...");  
	//using SecurityProviderTpm security = new SecurityProviderTpmHsm("MyRegistraton12345678");   
    using SecurityProviderTpm security = new SecurityProviderTpmHsm(null); // Registration Id  
  
	Console.WriteLine("Creating TPM authentication for IoT Hub...");  
	IAuthenticationMethod auth = new DeviceAuthenticationWithTpm(deviceId, security);  
  
	var _idScope = "myScopeId";  
	var _registrationId = "MyRegistraton12345678";  
	//var _endorsementKey = Convert.ToBase64String(security.GetEndorsementKey());  
	//var _storageRootKey = Convert.ToBase64String(security.GetStorageRootKey());  
	var _endorsementKey = security.GetEndorsementKey().ToString();  
	var _storageRootKey = security.GetStorageRootKey().ToString();  
  
	string webApiUrl = $"https://global.azure-devices-provisioning.net/{_idScope}/registrations/{_registrationId}?api-version=2021-06-01";  
  
	var tpm = new Tpm  
	{  
		EndorsementKey = _endorsementKey,  
		StorageRootKey = _storageRootKey  
	};  
  
	var requestBody = new RequestBody  
	{  
		Payload = "",  
		RegistrationId = _registrationId,  
		Tpm = tpm  
	};  
  
	var requestBodySerialized = JsonSerializer.Serialize(requestBody);  
  
	using (var client = new HttpClient())  
	{  
		StringContent httpContent = new StringContent(requestBodySerialized, System.Text.Encoding.UTF8, "application/json");  
  
		HttpResponseMessage response = await client.PostAsync(webApiUrl, httpContent);  
		if (!response.IsSuccessStatusCode)   
		{  
			Console.WriteLine("");  
			Console.WriteLine("API Call Failed!");   
		}  
		else   
		{  
			Console.WriteLine("");  
			Console.WriteLine(await response.Content.ReadAsStringAsync());   
		}  
	}  
}  

When reviewing the API Docs, I believe I'm including the necessary properties in the request body: