标签：asp-net-mvc-5 entity-framework-6 datetime sql c

当我尝试在MVC5中使用EF6初始化数据库时,出现错误：属性“ Timestamp”不是字节数组.只能为字节数组属性配置IsRowVersion.有没有一种方法可以使用FluentAPI覆盖IsRowVersion,还是有另一种方法可以使用MVC5 EF6存储DateTime,或者这仅仅是使用Timestamp数据注释的结果？我更喜欢存储为DateTime而不是字节数组.只是为了可视化,模型看起来像这样：

    public class UserProfile : IdentityUser
    {

        //ctor
        public UserProfile()
        {
            Random rnd = new Random();
            int pic = rnd.Next(1, 6); 

            DateJoined = DateTime.Now;
            UserLevel = 4;
            ImageUrl = "/Content/Avatars/Samples/sample" + pic + ".jpg"; // or append .jpg which == .jpg
        }

        public UserProfile(string name, string url)
        {
            UserName = name;
            DateJoined = DateTime.Now;
            UserLevel = 4;
            ImageUrl = url;
            Email = "your@email.com";
        }

        public UserProfile(string name, string url, string email)
        {
            Random rnd = new Random();
            int pic = rnd.Next(1, 6);
            UserName = name;
            DateJoined = DateTime.Now;
            UserLevel = 4;
            ImageUrl = "/Content/Avatars/sample" + pic + ".jpg"; // or append .jpg which == .jpg
            Email = email;
        }
        [Key]
        [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
        public int UserId { get; set; }
        [Required(ErrorMessage="*Username is required."), RegularExpression(@"^[\p{L} \p{Nd}_]+$")]
         [MinLengthAttribute(5, ErrorMessage="Not enough characters! UserName must be at least 5 chars."), MaxLengthAttribute(30,ErrorMessage="Too many characters in UserName!")]
        public override string UserName { get; set; }
        [Required(ErrorMessage="*Email is required."), EmailAddress, RegularExpression(@"\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*")]
        [DataType(DataType.EmailAddress)]
        [Display(Name = "Email address")]
        public string Email { get; set; }
        [ScaffoldColumn(false),Required]
        public string ImageUrl { get; set; }
        [DisplayFormat(DataFormatString = "{0}")] //{0:d} or {0:D}
        [DataType(DataType.DateTime), Timestamp, ScaffoldColumn(false)] //<--Problem 
        public DateTime DateJoined { get; set; }
        [Range(1, 6), ScaffoldColumn(false)]
        public int UserLevel { get; set; }
        [ScaffoldColumn(false)]
        public int? TotalRepPoints { get; set; }
        [ScaffoldColumn(false)]
        public virtual IDictionary<int, int> TotalPointsByCat { get; set; }
        // int = CategoryId, int = UserRank
        public virtual IDictionary<int, int> Rankings { get; set; }
        public virtual ICollection<Article> Articles { get; set; }
        public virtual ICollection<Answer> Answers { get; set; }
        public virtual ICollection<Vote> Votes { get; set; }
        public virtual ICollection<Question> Questions { get; set; }

    }

当我使用NuGet控制台时：

 PM> Enable-Migrations -Force
Checking if the context targets an existing database...
System.InvalidOperationException: The property 'Timestamp' is not a Byte array. IsRowVersion can only be configured for Byte array properties.
   at System.Data.Entity.ModelConfiguration.Configuration.ConventionPrimitivePropertyConfiguration.IsRowVersion()
   at System.Data.Entity.ModelConfiguration.Conventions.TimestampAttributeConvention.Apply(ConventionPrimitivePropertyConfiguration configuration, TimestampAttribute attribute)
   at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command)
...
    The property 'Timestamp' is not a Byte array. IsRowVersion can only be configured for Byte array properties.
    PM> 

提前致谢！

编辑

使用数据注释存储属性时[DataType(DataType.DateTime)]
与DateTime？类,您将在SQL中获得datetime类型字段.

使用数据注释存储属性时[时间戳记]
使用byte [],您将获得SQL中的时间戳记类型字段.

解决方法:

从Microsoft documentation on timestamp (AKA rowversion)(添加重点)开始：

Is a data type that exposes automatically generated, unique binary numbers within a database. rowversion is generally used as a mechanism for version-stamping table rows. The storage size is 8 bytes. The rowversion data type is just an incrementing number and does not preserve a date or a time. To record a date or time, use a datetime2 data type.

因此,尽管这个数据类型起了旧名称,但实际上与我们通常认为的实际日期时间值无关.

选择其他列类型,例如datetime.

标签：asp-net-mvc-5,entity-framework-6,datetime,sql,c
来源： https://codeday.me/bug/20191029/1962808.html

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