Not able to read spread sheet , getting error - google-sheets

Question

I am getting the error
An unhandled exception of type 'Google.GoogleApiException' occurred in mscorlib.dll Additional information: Google.Apis.Requests.RequestError
The caller does not have permission [403]
Errors [ Message[The caller does not have permission] Location[ - ] Reason[forbidden] Domain[global] ]
or
Request had invalid authentication credentials. Expected OAuth 2 access token, login cookie or other valid authentication credential.
See https://developers.google.com/identity/sign-in/web/devconsole-project. [401]
please let me know what i need to edit
string AccountFilePath = #"C:\GFApps\My App\Google Service\ServiceAccount\Json\CREG Service-427e7b31069c.json";
string AccountEmail = "cregadmin#creg-service.iam.gserviceaccount.com";
string AccountAdminUser = "googleIntegration.NET#domain.com";
string UserToImpersonate = null;
ServiceAccountCredential credential;
var credentialParameters = NewtonsoftJsonSerializer.Instance.Deserialize<JsonCredentialParameters>(File.ReadAllText(AccountFilePath));
using (var stream = new FileStream(AccountFilePath, FileMode.Open, FileAccess.Read)) {
credential = ServiceAccountCredential.FromServiceAccountData(stream);
}
var credentialforuser = new ServiceAccountCredential(new ServiceAccountCredential.Initializer(AccountEmail) {
Scopes = Scopes,
User = string.IsNullOrEmpty(UserToImpersonate) ? AccountAdminUser : UserToImpersonate,
Key = credential.Key
} .FromPrivateKey(credentialParameters.PrivateKey));
Console.WriteLine("read from spread sheet ");
// Create Google Sheets API service.
var service = new SheetsService(new BaseClientService.Initializer() {
HttpClientInitializer = credentialforuser,
ApplicationName = ApplicationName,
});
// Define request parameters.
String spreadsheetId = "1BxiMVs0XRA5nFMdKvBdBZjgmUUqptlbs74OgvE2upms";
// String spreadsheetId = "1nWdSM90mG7qT8YcOucHc_3NdmLYLpZd3FPJOF4lXMhY";
String range = "Class Data!A2:E";
SpreadsheetsResource.ValuesResource.GetRequest request =
service.Spreadsheets.Values.Get(spreadsheetId, range);
// Prints the names and majors of students in a sample spreadsheet:
// https://docs.google.com/spreadsheets/d/1BxiMVs0XRA5nFMdKvBdBZjgmUUqptlbs74OgvE2upms/edit
ValueRange response = request.Execute();
IList<IList<Object>> values = response.Values;
if (values != null && values.Count > 0) {
Console.WriteLine("Name, Major");
foreach (var row in values) {
// Print columns A and E, which correspond to indices 0 and 4.
Console.WriteLine("{0}, {1}", row[0], row[4]);
}
} else {
Console.WriteLine("No data found.");
}

Answer 1

You appear to be using a service account. Service accounts need to be pre authorized. Useing the service account email address share your sheet with the service account like you would any other user it will then have access to see your sheet
/// <summary>
/// Authenticating to Google using a Service account
/// Documentation: https://developers.google.com/accounts/docs/OAuth2#serviceaccount
/// </summary>
/// <param name="serviceAccountEmail">From Google Developer console https://console.developers.google.com</param>
/// <param name="serviceAccountCredentialFilePath">Location of the .p12 or Json Service account key file downloaded from Google Developer console https://console.developers.google.com</param>
/// <returns>AnalyticsService used to make requests against the Analytics API</returns>
public static SheetsService AuthenticateServiceAccount(string serviceAccountEmail, string serviceAccountCredentialFilePath, string[] scopes) {
try
{
    if (string.IsNullOrEmpty(serviceAccountCredentialFilePath))
    throw new Exception("Path to the service account credentials file is required.");
    if (!File.Exists(serviceAccountCredentialFilePath))
        throw new Exception("The service account credentials file does not exist at: " + serviceAccountCredentialFilePath);
    if (string.IsNullOrEmpty(serviceAccountEmail))
throw new Exception("ServiceAccountEmail is required.");
    // For Json file
    if (Path.GetExtension(serviceAccountCredentialFilePath).ToLower() == ".json")
    {
        GoogleCredential credential;
        using (var stream = new FileStream(serviceAccountCredentialFilePath, FileMode.Open, FileAccess.Read))
        {
         credential = GoogleCredential.FromStream(stream).CreateScoped(scopes);
}
        // Create the Analytics service.
        return new SheetsService(new BaseClientService.Initializer()
        {
         HttpClientInitializer = credential,
            ApplicationName = "Sheets Service account Authentication Sample",
});
}
    else if (Path.GetExtension(serviceAccountCredentialFilePath).ToLower() == ".p12")
    { // If its a P12 file
     var certificate = new X509Certificate2(serviceAccountCredentialFilePath, "notasecret", X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.Exportable);
        var credential = new ServiceAccountCredential(new ServiceAccountCredential.Initializer(serviceAccountEmail)
        {
         Scopes = scopes
} .FromCertificate(certificate));
      // Create the Sheets service.
        return new SheetsService(new BaseClientService.Initializer()
        {
         HttpClientInitializer = credential,
            ApplicationName = "Sheets Authentication Sample",
});
}
    else
    {
     throw new Exception("Unsupported Service accounts credentials.");
}
}
catch (Exception ex)
{
throw new Exception("CreateServiceAccountSheetsFailed", ex);
}
}
link to the above sample https://github.com/LindaLawton/Google-Dotnet-Samples/blob/master/Samples/Google%20Sheets%20API/v4/ServiceAccount.cs