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Emanuele Bartolesi
Emanuele Bartolesi

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Hackathon - Hack Together: Microsoft Graph and .NET 🦒 - Day 04

Today I fixed the issue that I had yesterday about retrieving data from a CalendarView from the user’s calendar.
I asked for help to two friends of mine (Patrick and Federico) because I wasted 3 hours on the same issue.
After a quick brainstorming (via chat) I figured out what is the problem.
Maybe during my tests I created an App Registration and I consented a permission called “Calendar.ReadBasic” and then I tried to call the Graph SDK with another permission in the scope as “Calendars.ReadWrite”.
In my token I had both scope and of course the less security scope win and I obtained “Access Denied”.
I deleted my App Registration and I created a new one with the right permission and it started to work well. 😊

Lesson learned.

What I have now in my appsettings.json file:

  "AzureAd": {
    "Authority": "",
    "ClientId": "5c1b3387-b2ca-4513-83e7-3c802665bea0",
    "ValidateAuthority": true
  "GraphScopes": "Files.Read;Tasks.ReadWrite;User.Read;MailboxSettings.Read;email;offline_access;openid;profile;Mail.Read;Calendars.ReadWrite"
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And now to retrieve the data from the calendar I wrote the following code:

        // Get the user
        var user = (await authenticationStateTask).User;
        var graphTimeZone = user.GetUserGraphTimeZone();
        dateTimeFormat = $"{user.GetUserGraphDateFormat()} {user.GetUserGraphTimeFormat()}";

        // Calculate the start and end of the current week in user's time zone
        var startOfWeek = GetUtcStartOfWeekInTimeZone(DateTime.Today, graphTimeZone);
        var endOfWeek = startOfWeek.AddDays(7);

        graphClient = clientFactory.GetAuthenticatedClient();

        // Specifies the start and end of the view on the calendar
        // Translates to: ?startDateTime=""&endDateTime=""
        var viewOptions = new List<QueryOption>
            new QueryOption("startDateTime", startOfWeek.ToString("o")),
            new QueryOption("endDateTime", endOfWeek.ToString("o"))

        var eventPage = await graphClient.Me
            .Header("Prefer", $"outlook.timezone=\"{graphTimeZone}\"")
            .Select(e => new

        events = eventPage.CurrentPage;
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As you can see at the beginning I try to retrieve some information from the user profile like the TimeZone and the date format.

Then I retrieve the items for the current week and I collect them in a List.
Now I am ready to display all the items in our homepage.

I think tomorrow I will create at least four components to display all the data I have now: Calendar items, Mails and Todos.

    var mail = await graphClient.Me.Messages.Request().OrderBy("receivedDateTime desc").GetAsync();
     var todos = await graphClient.Me.Todo.Lists.Request().GetAsync();
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In the code above you can see how I retrieve the emails (ordered by received date and time descending).
I have to work on the Todos items because at the beginning I need to retrieve all the lists (as in the code above) and then from each lists I need to retrieve the items that expired today.

I think I am on track with all the activities for the due date of the Hackathon.

Stay tuned.

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