Entity Framework - Azure Table Storage Provider - Error While Mapping Timestamp

Question

I am currently accessing an Azure Storage Table using EF: EntityFramework.AzureTableStorage 7.0.0-beta1

When configuring the model, I've mapped the timestamp property of the TableEntity to a property of my model :

public class Subscription
{
    public string Environment { get; set; }

    public string Name { get; set; }

    public DateTimeOffset LastModification { get; set; }

    ...
    ...            
}

public class EF7Context : DbContext
{
    public DbSet<Subscription> Subscriptions { get; set; }

    protected override void OnConfiguring(DbContextOptions options)
    {
        options.UseAzureTableStorage("MyconnectionString");
    }

    protected override void OnModelCreating(Microsoft.Data.Entity.Metadata.ModelBuilder modelBuilder)
    {
        // Configure the Azure Table Storage
        modelBuilder.Entity<Subscription>()
            .ForAzureTableStorage() // Data are stored in an Azure Table Storage.
            .Table("SubscriptionDev") // Name of the Table in the Azure Storage Account
            .Timestamp(s => s.LastModification) // Map the timestamp
            .PartitionAndRowKey(s => s.Environment, s => s.Name); // Map the partition and the row key
    }
}

When inserting new entity, every thing sounds good, I can retrieve the newly created entity with the LastModification but if I instanciate a second DbContext, I can't retrieve my entity:

using (var context = new EF7Context())
{
    // Create the entity
    var subscription = new Subscription() {Environment = "Dev", Name = "subscriptionName" };
    context.Subscriptions.Add(subscription);
    context.SaveChanges();

    // Retrieve the entity in the same context => I assume entity has been cached ?
    subscription = context.Subscriptions.SingleOrDefault(s => s.Name == "subscriptionName");
}

// Create new instance of the DbContext
using (var context = new EF7Context())
{
    // Exception thrown here
    var subscription = context.Subscriptions.SingleOrDefault(s => s.Name == "subscriptionName");
}

Exception details:

Microsoft.WindowsAzure.Storage.StorageException was unhandled HResult=-2146233088 Message=Cannot read value of type 'DateTimeOffset' from '13' Source=Microsoft.WindowsAzure.Storage

It seems that the mapping does not work while retrieving data from the Azure Storage Account.

Does anyone know a workaround (except removing the timestamp mapping) ?

natemcmaster natemcmaster · Accepted Answer · 2016-02-03T22:28:02

As mentioned before, EF Azure Table Storage beta1 was a prototype that has been discontinued for now. See also https://stackoverflow.com/a/35071077/2526265. It is not under active development (at time of writing).

Entity Framework - Azure Table Storage Provider - Error While Mapping Timestamp

1 Answers