Question

我目前正在使用EF访问Azure存储表：EntityFramework.AzureTableStorage 7.0.0-beta1

配置模型时，我已将TableEntity的timestamp属性映射到我的模型的属性：

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
    }
}

当插入新实体时，每件事听起来都不错，我可以使用LastModification检索新创建的实体，但如果我实例化第二个DbContext，我就无法检索我的实体：

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");
}

异常详情：

Microsoft.WindowsAzure.Storage.StorageException未处理的HResult = -2146233088 Message =无法从'13'读取'DateTimeOffset'类型的值源= Microsoft.WindowsAzure.Storage

从Azure存储帐户检索数据时，映射似乎不起作用。

有没有人知道解决方法（除了删除时间戳映射）？

Answer 1

如前所述，EF Azure Table Storage beta1是原型，目前已停产。另见https://stackoverflow.com/a/35071077/2526265。它没有得到积极的发展（在撰写本文时）。

实体框架 - Azure表存储提供程序 - 映射时间戳时出错

1 个答案: