managed_identity_keyvault_example.cs

private static IKeyVaultClient CreateKeyVaultWithManagedIdentity(string userIdentityId)
{
  AzureServiceTokenProvider azureServiceTokenProvider;
  if (!string.IsNullOrEmpty(userIdentityId))
  {
      // use User Managed Identity
      azureServiceTokenProvider = new AzureServiceTokenProvider($"RunAs=App;AppId={userIdentityId}");
  } else
  {
      // use System Managed Identity
      azureServiceTokenProvider = new AzureServiceTokenProvider();
  }
  var keyVaultClient = new KeyVaultClient(
      new KeyVaultClient.AuthenticationCallback(
         azureServiceTokenProvider.KeyVaultTokenCallback));
  return keyVaultClient;
}