C# GraphAPIでOneDriveにExcelを新規作成するサンプルプログラム

アクセストークン取得:方法1

        string accessToken ="";
        //API URL
        var url = "https://login.microsoftonline.com/{tenant_id}/oauth2/v2.0/token";

        var httpRequest = (HttpWebRequest)WebRequest.Create(url);
        httpRequest.Method = "POST";

        httpRequest.ContentType = "application/x-www-form-urlencoded";

        var data = "grant_type=client_credentials&scope=https%3A%2F%2Fgraph.microsoft.com%2F.default&client_id=535fb089-9ff3-47b6-9bfb-4f1264799865&client_secret=qWgdYAmab0YSkuL1qKv5bPX";

        using (var streamWriter = new StreamWriter(httpRequest.GetRequestStream()))
        {
            streamWriter.Write(data);
        }

        
        var httpResponse = (HttpWebResponse)httpRequest.GetResponse();

        using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
        {
            var result = streamReader.ReadToEnd();
            dynamic dataArr = JOBject.Parse(result);
            accessToken = dataArr.access_token;
        }

        Console.WriteLine(httpResponse.StatusCode);

アクセストークン取得：方法②

using Microsoft.Graph;

var scopes = new string[] { "https://graph.microsoft.com/.default" };

// Configure the MSAL client as a confidential client
var confidentialClient = ConfidentialClientApplicationBuilder
    .Create(clientId)
    .WithAuthority($"https://login.microsoftonline.com/$tenantId/v2.0")
    .WithClientSecret(clientSecret)
    .Build();

// Retrieve an access token for Microsoft Graph (gets a fresh token if needed).
var authResult = await confidentialClient
                .AcquireTokenForClient(scopes)
                .ExecuteAsync();

//認証
var authProvider = new DelegateAuthenticationProvider(request =>
{
                    request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", authResult.AccessToken);
                    return Task.CompletedTask;
                });

認証

            //認証
            var authProvider = new DelegateAuthenticationProvider(request =>
            {
                request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", "ここにアクセストークンを入力してください");
                return Task.CompletedTask;
            });
            var graphClient = new GraphServiceClient(authProvider);

            //OneDriveにExcelを新規作成
            using (var stream = new MemoryStream())
            {
                
                CreateWorkbook(stream);
                stream.Seek(0, SeekOrigin.Begin);
                var driveItem = await graphClient.Users["O365のユーザID"]
                        .Drive
                        .Root
                        .ItemWithPath("testExcel.xlsx")
                        .Content
                        .Request()
                        .PutAsync<DriveItem>(stream);

            }
            //OneDriveのファイルをリスト
            IDriveItemChildrenCollectionPage items = await graphClient.Users["O365のユーザID"].Drive.Root.Children.Request().GetAsync();

エクセル作成

//エクセル作成
 public static void CreateWorkbook(Stream stream)
        {

            // By default, AutoSave = true, Editable = true, and Type = xlsx.
            var spreadsheetDocument =
                SpreadsheetDocument.Create(stream, SpreadsheetDocumentType.Workbook);

            // Add a WorkbookPart to the document.
            var workbookpart = spreadsheetDocument.AddWorkbookPart();
            workbookpart.Workbook = new DocumentFormat.OpenXml.Spreadsheet.Workbook();

            // Add a WorksheetPart to the WorkbookPart.
            var worksheetPart = workbookpart.AddNewPart<WorksheetPart>();
            worksheetPart.Worksheet = new Worksheet(new SheetData());
            // Add Sheets to the Workbook.
            var sheets = spreadsheetDocument.WorkbookPart.Workbook.AppendChild<Sheets>(new Sheets());

            // Append a new worksheet and associate it with the workbook.
            var sheet = new Sheet()
            { Id = spreadsheetDocument.WorkbookPart.GetIdOfPart(worksheetPart), SheetId = 1, Name = "mySheet" };
            sheets.Append(sheet);

            workbookpart.Workbook.Save();
            // Close the document.
            spreadsheetDocument.Close();
        }

参照