Microsoft Graph API To Do List Call (Cannot Convert ITodoListCollectionPage to Todo)

Question

I am creating a .Net Core application in which a user can login/logout with their microsoft 365 account and also view their Task Lists/Tasks via the Microsoft Graph API. I am currently trying to request the list via the API using.

Controller.cs

 [AuthorizeForScopes(ScopeKeySection = "DownstreamApi:Scopes")]
        public async Task<IActionResult> Tasks()
        {
            User currentUser = null;
            Todo currentLists = null;

            try 
            {
                currentUser = await _graphServiceClient.Me.Request().GetAsync();
                currentLists = await _graphServiceClient.Me.Todo.Lists.Request().GetAsync();

            }
            catch (ServiceException svcex) when (svcex.Message.Contains("Continuous access evaluation resulted in claims challenge"))
            {
                try
                {
                    Console.WriteLine($"{svcex}");
                    string claimChallenge = WwwAuthenticateParameters.GetClaimChallengeFromResponseHeaders(svcex.ResponseHeaders);
                    _consentHandler.ChallengeUser(_graphScopes, claimChallenge);
                    return new EmptyResult();
                }
                catch (Exception ex2)
                {
                    _consentHandler.HandleException(ex2);
                }
            }

            ViewData["Me"] = currentUser;
            ViewData["Lists"] = currentLists;
            return View();
        }

However this throws an issue where

currentLists = await _graphServiceClient.Me.Todo.Lists.Request().GetAsync();

Cannot convert to the Todo type in order for me to then use the data on the following cshtml page

@using Newtonsoft.Json.Linq
@{
    ViewData["Title"] = "User Profile fetched from MS Graph";
    Layout = "~/Views/Shared/_Layout.cshtml";
}
<br />
<br />

<table class="table table-striped table-condensed" style="font-family: monospace" border="1">
    <thead>
        <tr>
        </tr>
        @{
            var lists = ViewData["lists"] as Microsoft.Graph.TodoTaskList;
            <tr>
                <th>
                    ID
                </th>
                <th>
                    @lists.DisplayName
                </th>
                <th></th>
            </tr>
        }
    </thead>
    <tbody>
    </tbody>

Where converting currentLists to the type suggested "ITodoListCollectionsPage" causes the web application to now allow access to the data requested.

How can I fix this and call the Microsoft Graph API to get the Todo Task Lists and output that correctly

score 1 · Accepted Answer · answered Feb 17 '22 at 11:29

await _graphServiceClient.Me.Todo.Lists.Request().GetAsync(); returns ITodoListCollectionsPage.

You need to iterate through all pages and get all ToDo task lists.

var currentLists = new List<TodoTaskList>();
var todoListsPage = await _graphServiceClient.Me.Todo.Lists.Request().GetAsync();
currentLists.AddRange(todoListsPage.CurrentPage.ToList());
while (todoListsPage.NextPageRequest != null)
{
    todoLists = await todoListsPage.NextPageRequest.GetAsync();
    currentLists.AddRange(todoListsPage.CurrentPage.ToList());
}

If you want to get todo tasks you need to make another request for each TodoTaskList in List<TodoTaskList>

Only example how to get todo tasks:

var todoTasksDict = new Dictionary<string, List<TodoTask>>();
foreach (var todoList in currentLists)
{
    var todoTasks = new List<TodoTask>();
    var todoTasksPage = await client.Me.Todo.Lists[todoList.Id].Tasks.Request().GetAsync();
    todoTasks.AddRange(todoTasksPage.CurrentPage.ToList());
    while (todoTasksPage.NextPageRequest != null)
    {
        todoTasksPage = await todoTasksPage.NextPageRequest.GetAsync();
        todoTasks.AddRange(todoTasksPage.CurrentPage.ToList());
    }
    todoTasksDict[todoList.DisplayName] = todoTasks;
}

I don't know how do you want to display todo task lists and related todo tasks but you will need to modify your views.

Microsoft Graph API To Do List Call (Cannot Convert ITodoListCollectionPage to Todo)

1 Answers1