entity-framework - RIA 服务 + Entity Framework 4 + POCO 的 : 'The Timestamp field is required' error?

Question

我在 MSSQL 中定义了下表:

CREATE TABLE [User] ( 
    [Id] bigint identity(1,1)  NOT NULL,
    [Email] nvarchar(256),
    [PasswordHash] nvarchar(128) NOT NULL,
    [PasswordFormat] int DEFAULT ((0)) NOT NULL,
    [PasswordSalt] nvarchar(10) NOT NULL,
    [Timestamp] timestamp
)
;

Timestamp 的 EDMX 属性如下所示:(请注意只有红色属性已被我手动更改)

我使用 t4 模板自动生成 POCO 实体。用户实体如下所示:

public partial class User : IEntity
{
    public virtual long Id
    {
        get;
        set;
    }
    ...

    [TimestampAttribute]
    [ConcurrencyCheck]
    [SuppressMessage("Microsoft.Performance", "CA1819:PropertiesShouldNotReturnArrays", Justification = "Autogenerated by T4.")]
    public virtual byte[] Timestamp
    {
        get;
        set;
    }

    ...
}

在 ObjectContext 上执行“SaveChanges”操作时，我收到名为 User 实体的验证错误:The Timestamp field is required

Answer 1

解决方法:

我已将 T4 生成的用户类更改为:(删除了“ConcurrencyCheck”属性)

public partial class User : IEntity
{
    public virtual long Id
    {
        get;
        set;
    }
    ...

    [TimestampAttribute]
    [SuppressMessage("Microsoft.Performance", "CA1819:PropertiesShouldNotReturnArrays", Justification = "Autogenerated by T4.")]
    public virtual byte[] Timestamp
    {
        get;
        set;
    }

    ...
}

我添加了一个通用元数据类，所有实体都使用它，不包括 Timestamp 属性:

/// <summary>
/// A MetaData which defines some default metadata for an Entity
/// </summary>
public class EntityMetaData
{
    /// <summary>
    /// Initializes a new instance of the <see cref="EntityMetaData"/> class.
    /// </summary>
    protected EntityMetaData()
    {
    }

    /// <summary>
    /// Gets or sets the timestamp.
    /// Note : this field is excluded on the client.
    /// </summary>
    /// <value>The timestamp.</value>
    [Exclude]
    public byte[] Timestamp { get; set; }
}

这解决了问题。