Azure Offline Sync - Uncaught Exception

Question

I am using Xamarin Forms and Azure in an attempt to implement offline sync in my mobile app to store a list of Machine objects.

In my class that handles offline sync, I have a function called Initialize(), for setting up a local database in my phone or tablet, for offline sync

    public MobileServiceClient client { get; set; }
    IMobileServiceSyncTable<Machine> machineTable;

    public async Task Initialize()
    {
        if (client?.SyncContext?.IsInitialized ?? false)
        {
            return;
        }
        var azureUrl = "http://mycoolwebsite.azurewebsites.net";

        //Create our client
        client = new MobileServiceClient(azureUrl);

        //InitialzeDatabase for path
        var path = "mylocaldb.db";
        path = Path.Combine(MobileServiceClient.DefaultDatabasePath, path);

        //setup our local sqlite store and intialize our table
        var store = new MobileServiceSQLiteStore(path);

        //Define table
        store.DefineTable<Machine>();

        //Initialize SyncContext -- Populate the local DB!
        await client.SyncContext.InitializeAsync(store, new MobileServiceSyncHandler());  //<-- EXCEPTION HERE
        machineTable = client.GetSyncTable<Machine>(); 
        // table.PurgeAsync();
    }

When I run this code, I run into an exception on the line I have highlighted above. What am I missing? For reference, I am following this tutorial.

Answer 1

It turns out that when using:

    await client.SyncContext.InitializeAsync(store, new MobileServiceSyncHandler());
    machineTable = client.GetSyncTable<Machine>(); 

I needed to have an public string Id { get; set; } variable in my Machine object, as the code for building the local db requires this field. Would be nice if this was added to the documentation somewhere!