title: C# Google Drive API Error " Google.Apis.Services.BaseClientService.Initializer' does not contain a definition for 'Authenticator' "
body: <p>I am trying a sample code with domain wide delegation of authority.  I am implementing the code specified in this link: <a href="https://developers.google.com/drive/web/delegation" rel="nofollow">https://developers.google.com/drive/web/delegation</a></p>
  
  <pre><code>    private DriveService GetService(String userEmail)
      {
  
          X509Certificate2 certificate = new X509Certificate2(SERVICE_ACCOUNT_PKCS12_FILE_PATH, "notasecret", X509KeyStorageFlags.Exportable);
  
          var provider = new AssertionFlowClient(GoogleAuthenticationServer.Description, certificate)
          {
              ServiceAccountId = SERVICE_ACCOUNT_EMAIL,
              Scope = DriveService.Scope.Drive.GetStringValue(),
              ServiceAccountUser = userEmail,
          };
  
          authenticator = new OAuth2Authenticator&lt;AssertionFlowClient&gt;(provider, AssertionFlowClient.GetState);
  
  
          return new DriveService(new BaseClientService.Initializer() { Authenticator = authenticator, ApplicationName = "sample" });
  
      }
  </code></pre>
  
  <p>When i compile it i am getting an error saying "'Google.Apis.Services.BaseClientService.Initializer' does not contain a definition for 'Authenticator' ". i think its because of a recent change to the API. So can someone please suggest as to how to overcome this error?</p>