Able to write POCO to Firebase Firestore but not able to read back

[dvillavicencio-mfe]

Hi, I have a small issue with my .NET Maui app whilst writing and reading back from Firestore for cloud syncing. I have the following POCOs:

CrewCheckInObject (top-most object in the hierarchy)

public class CrewCheckIn : IFirestoreObject
{
    public CrewCheckIn()
    {
    }

    public CrewCheckIn(List<CrewCheckInEmployee> employees, List<CrewCheckInAsset> yardAssets, string clockInTime, string yardLocation, bool emergencyCheckIn, List<CrewCheckInRemovedAsset> removedAssets, List<CrewCheckInLog> logEntries, DateTime timestamp)
    {
        Employees = employees;
        YardAssets = yardAssets;
        ClockInTime = clockInTime;
        YardLocation = yardLocation;
        EmergencyCheckIn = emergencyCheckIn;
        RemovedAssets = removedAssets;
        LogEntries = logEntries;
        Timestamp = timestamp;
    }

    [FirestoreProperty("employees")]
    public IList<CrewCheckInEmployee> Employees { get; set; }

    [FirestoreProperty("yardAssets")]
    public IList<CrewCheckInAsset> YardAssets { get; set; }

    [FirestoreProperty("clockInTime")]
    public string ClockInTime { get; set; }

    [FirestoreProperty("yardLocation")]
    public string YardLocation { get; set; }

    [FirestoreProperty("emergencyCheckIn")]
    public bool EmergencyCheckIn { get; set; }

    [FirestoreProperty("removedAssets")]
    public IList<CrewCheckInRemovedAsset> RemovedAssets { get; set; }

    [FirestoreProperty("logs")]
    public IList<CrewCheckInLog> LogEntries { get; set; }

    [FirestoreProperty("timestamp")]
    public DateTime Timestamp { get; set; }
}

CrewCheckInEmployee

public class CrewCheckInEmployee : IFirestoreObject
{

    public CrewCheckInEmployee() { }

    public CrewCheckInEmployee(string name, string clazz, int crew, List<string> languages, List<CrewCheckInAsset> assignedEquipment, List<CrewCheckInAsset> assignedVehicles, string clockInTime, string status, string workType, List<string> jobNumbers, string notes)
    {
        Name = name;
        Clazz = clazz;
        Crew = crew;
        Languages = languages;
        AssignedEquipment = assignedEquipment;
        AssignedVehicles = assignedVehicles;
        ClockInTime = clockInTime;
        Status = status;
        WorkType = workType;
        JobNumbers = jobNumbers;
        Notes = notes;
    }

    [FirestoreProperty("name")]
    public string Name { get; set; }

    [FirestoreProperty("class")]
    public string Clazz { get; set; }

    [FirestoreProperty("crew")]
    public int Crew { get; set; }

    [FirestoreProperty("languages")]
    public IList<string> Languages { get; set; }

    [FirestoreProperty("assignedEquipment")]
    public IList<CrewCheckInAsset> AssignedEquipment { get; set; }

    [FirestoreProperty("assignedVehicles")]
    public IList<CrewCheckInAsset> AssignedVehicles { get; set; }

    [FirestoreProperty("clockInTime")]
    public string ClockInTime { get; set; }

    [FirestoreProperty("status")]
    public string Status { get; set; }

    [FirestoreProperty("workType")]
    public string WorkType { get; set; }

    [FirestoreProperty("jobNumbers")]
    public IList<string> JobNumbers { get; set; }

    [FirestoreProperty("notes")]
    public string Notes { get; set; }
}

Crew Check In Log

public class CrewCheckInRemovedAsset : IFirestoreObject
{

    public CrewCheckInRemovedAsset() { }

    public CrewCheckInRemovedAsset(string assetName, string assetDescription, string reason)
    {
        AssetName = assetName;
        AssetDescription = assetDescription;
        Reason = reason;
    }

    [FirestoreProperty("assetName")]
    public string AssetName { get; private set; }

    [FirestoreProperty("assetDescription")]
    public string AssetDescription { get; private set; }

    [FirestoreProperty("reason")]
    public string Reason { get; private set; }
}

Crew Check In Log

public class CrewCheckInLog : IFirestoreObject
{
    public CrewCheckInLog() { }

    public CrewCheckInLog(DateTime timestamp, string action, string message)
    {
        Timestamp = timestamp;
        Action = action;
        Message = message;
    }

    [FirestoreProperty("timestamp")]
    public DateTime Timestamp { get; set; } // Plugin.Firebase maps to Firestore timestamp

    [FirestoreProperty("action")]
    public string Action { get; set; }

    [FirestoreProperty("message")]
    public string Message { get; set; }
}

Crew Check In Asset

public class CrewCheckInAsset : IFirestoreObject
{
    public CrewCheckInAsset() { }

    public CrewCheckInAsset(string description, string name, string @operator, string type)
    {
        Description = description;
        Name = name;
        Operator = @operator;
        Type = type;
    }

    [FirestoreProperty("description")]
    public string Description { get; set; }

    [FirestoreProperty("name")]
    public string Name { get; set; }

    [FirestoreProperty("operator")]
    public string Operator { get; set; }

    [FirestoreProperty("type")]
    public string Type { get; set;  }
}

I'm able to put this into Firestore correctly using the following snippet of code:

public async Task Sync(CrewCheckIn crewCheckIn)
{
    var document = _firebaseFirestore.GetDocument($"UserData/{Authentication.userUID}");
    await document.SetDataAsync(crewCheckIn);
}

however, when it comes to reading it back in the following snippet:

private partial async Task<CrewCheckIn> GetCrewCheckInImpl()
{
    var document = _firebaseFirestore.GetDocument($"UserData/{Authentication.userUID}");
    var snapshot = await document.GetDocumentSnapshotAsync<CrewCheckIn>();
    return snapshot.Data;
}

I get an NSObject exception that isn't being thrown when reading the .Data member of the snapshot object. I'm also testing this on iOS. I just wanted some clarification if something in my code is wrong that I don't see it or if its a deeper issue than what I think.

Any help is appreciated, thanks!

Edit: I'm adding the entire POCO structure and (hopefully) a useful stack trace. I didn't want to add as much because I don't want to code dump but I figured I would so we can see the issue at hand better.

Stack Trace when program crashes:

2025-02-27 14:48:02.625 Xamarin.PreBuilt.iOS[1410:418710] Plugin.Firebase.Firestore.Platforms.iOS.DocumentSnapshotWrapper`1[RGIHome.Dtos.CrewCheckIn]
Thread started: <Thread Pool> #53
[0:] An error occurred: 'Could not convert NSObject of type Foundation.NSObject to object'. Callstack: '   at Plugin.Firebase.Firestore.Platforms.iOS.Extensions.NSObjectExtensions.ToObject(NSObject this, Type targetType)
   at Plugin.Firebase.Firestore.Platforms.iOS.Extensions.NSObjectExtensions.Cast(NSDictionary this, Type targetType, String documentId)
   at Plugin.Firebase.Firestore.Platforms.iOS.Extensions.DictionaryExtensions.ToDictionaryObject(NSDictionary this, Type targetType)
   at Plugin.Firebase.Firestore.Platforms.iOS.Extensions.NSObjectExtensions.ToObject(NSObject this, Type targetType)
   at Plugin.Firebase.Firestore.Platforms.iOS.Extensions.ListExtensions.ToList(NSArray this, Type targetType)
   at Plugin.Firebase.Firestore.Platforms.iOS.Extensions.NSObjectExtensions.ToObject(NSObject this, Type targetType)
   at Plugin.Firebase.Firestore.Platforms.iOS.Extensions.NSObjectExtensions.Cast(NSDictionary this, Type targetType, String documentId)
   at Plugin.Firebase.Firestore.Platforms.iOS.Extensions.NSObjectExtensions.Cast[CrewCheckIn](NSDictionary this, String documentId)
   at Plugin.Firebase.Firestore.Platforms.iOS.DocumentSnapshotWrapper`1[[RGIHome.Dtos.CrewCheckIn, RGIHome, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].get_Data()
   at RGIHome.Repository.CrewCheckInRepository.GetCrewCheckIn() in C:\Users\Daniel\Source\Repos\RGIHome\RGIHome\Repository\CrewCheckInRepository.cs:line 76
   at RGIHome.Services.CheckInStateManager.SaveStateAsync() in C:\Users\Daniel\Source\Repos\RGIHome\RGIHome\Services\CheckInStateManagerService.cs:line 148
   at RGIHome.Services.CheckInViewModel.BackButton() in C:\Users\Daniel\Source\Repos\RGIHome\RGIHome\ViewModels\CheckInPage\CheckInViewModel.cs:line 118
   at CommunityToolkit.Mvvm.Input.AsyncRelayCommand.AwaitAndThrowIfFailed(Task executionTask)
   at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__128_0(Object state)
   at Foundation.NSAsyncSynchronizationContextDispatcher.Apply() in /Users/builder/azdo/_work/1/s/xamarin-macios/src/Foundation/NSAction.cs:line 179
   at UIKit.UIApplication.UIApplicationMain(Int32 argc, String[] argv, IntPtr principalClassName, IntPtr delegateClassName) in /Users/builder/azdo/_work/1/s/xamarin-macios/src/UIKit/UIApplication.cs:line 61
   at UIKit.UIApplication.Main(String[] args, Type principalClass, Type delegateClass) in /Users/builder/azdo/_work/1/s/xamarin-macios/src/UIKit/UIApplication.cs:line 96
   at RGIHome.Program.Main(String[] args) in C:\Users\Daniel\Source\Repos\RGIHome\RGIHome\Platforms\iOS\Program.cs:line 13
   at System.Object.InvokeStub_Program.Main(Object , Span`1 )
   at System.Reflection.MethodBaseInvoker.InvokeWithOneArg(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)'
The app has been terminated.The app has been terminated.

Edit #2: This code works on android, its an iOS issue.