Using C#, I am getting an error using Files.Get Google Drive API

Question

My overall project is to create a spreadsheet, populate it, move it to a new location and lock it.

So far creating the sheet and populating it is fine. However, when I attempt to move the file I get the following error:
Happens at this part of the code: var getRequest = DriveService.Files.Get(fileId);

System.NullReferenceException
HResult=0x80004003
Message=Object reference not set to an instance of an object.

My code is:

    static void Init()
    {

        UserCredential credential;

        //Reading Credentials File...
        using (var stream = new FileStream("client_secret.json", FileMode.Open, FileAccess.Read))
        {
            string credPath = System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal);               
            credPath = Path.Combine(credPath, ".credentials/sheets.googleapis.com-dotnet-quickstart.json");

            credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
                GoogleClientSecrets.FromStream(stream).Secrets,
                Scopes,
                "user",
                CancellationToken.None,
                new FileDataStore(credPath, true)).Result;

        }

        // Creating Google Sheets API service...
        SheetsService = new SheetsService(new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
            ApplicationName = ApplicationName,
        });

        // Create a Drive API service client
        DriveService DriveService = new DriveService(new Google.Apis.Services.BaseClientService.Initializer
        {
            HttpClientInitializer = credential,
            ApplicationName = ApplicationName,
        });

    }

    static void CreateSheet()
    {

        // Create a new sheet with a single tab
        string sheetName = "Test Create Sheet";
        var NewSheet = new Google.Apis.Sheets.v4.Data.Spreadsheet();
        NewSheet.Properties = new SpreadsheetProperties();
        NewSheet.Properties.Title = sheetName;
        
        var newSheet = SheetsService.Spreadsheets.Create(NewSheet).Execute();

        SpreadsheetId = newSheet.SpreadsheetId;

        Sheet = "Sheet1";

    }

    static void MoveSheet()
    {

        // Get the ID of the sheet you want to move
        string sheetId = SpreadsheetId;

        // Get the ID of the folder you want to move the sheet to
        string folderId = "XXXXXBeNF2rG0PA6bsi89YugahH-XXXX";

        // Retrieve the existing parents to remove
        string fileId = sheetId;

        var getRequest = DriveService.Files.Get(fileId);
        getRequest.Fields = "parents";
        var file = getRequest.Execute();
        var previousParents = String.Join(",", file.Parents);

        // Move the file to the new folder
        var updateRequest =
            DriveService.Files.Update(new Google.Apis.Drive.v3.Data.File(),
                fileId);
        updateRequest.Fields = "id, parents";
        updateRequest.AddParents = folderId;
        updateRequest.RemoveParents = previousParents;
        //file = updateRequest.Execute();

    }

@madreflection no, I understand what it is, but I don't understand why I am getting it despite having a valid sheetid/fileid. — warrenk, Dec 21 '22 at 23:06
Then you need to step through the code, determine whether it's `DriveService` or `DriveService.Files` that's `null`, and if you can't figure out why that specific thing is `null`, ask the question framed specifically for it. Questions framed the way this is will be closed as a duplicate because they don't show any effort beyond what the canonical post describes. — madreflection, Dec 21 '22 at 23:10

score 0 · Answer 1 · answered Dec 21 '22 at 23:46

It turns out I had a duplicate word (DriveService):

// Create a Drive API service client
    DriveService DriveService = new DriveService(new Google.Apis.Services.BaseClientService.Initializer
    {
        HttpClientInitializer = credential,
        ApplicationName = ApplicationName,
    });

}

Should have been this:

// Create a Drive API service client
    DriveService = new DriveService(new Google.Apis.Services.BaseClientService.Initializer
    {
        HttpClientInitializer = credential,
        ApplicationName = ApplicationName,
    });

}

I am now beyond that issue and have a new one in the form of:

The service drive has thrown an exception. HttpStatusCode is Forbidden. Insufficient Permission: Request had insufficient authentication scopes.

Using C#, I am getting an error using Files.Get Google Drive API

1 Answers1