解决方案:

如你所见:此处

• 对象上下文将打开尚未打开的连接手术前。如果对象上下文在一个操作，它在操作时总是会关闭连接就完成了。
• 如果您手动打开连接，对象上下文不会关闭它。调用Close或Dispose将关闭连接。

问题是EF会打开和关闭SetUserContext的连接，所以我会丢失CONTEXT_INFO。为了保持它，我需要手动打开连接，并在SaveChanges

public int SaveChanges(string modifierId)
{
        Database.Connection.Open();
        SetUserContext(modifierId);
        var changes = base.SaveChanges();
        Database.Connection.Close();
        return changes;            
 }

问题:

系统工作在一个数据仓库上。数据库必须知道谁修改了它，并将任何更改保存在审计表中。

为了达到这个结果，我主要依靠触发器和和过程:

此函数将userId保存在CONTEXT_INFO:

CREATE PROCEDURE [dbo].[SetUserContext]
    @userId NVARCHAR (64)
AS
BEGIN
    SET NOCOUNT ON;
    DECLARE @context VARBINARY(128)
    SET @context = CONVERT(VARBINARY(128), @userId)
    SET CONTEXT_INFO @context
END

这个可以在任何地方使用获取userId:

CREATE FUNCTION [dbo].[GetUserContext] ()
RETURNS NVARCHAR (64)
AS
BEGIN
    RETURN CONVERT(NVARCHAR (64), CONTEXT_INFO())
END

例如，在我的触发器中，我有:

CREATE TRIGGER UpdateUser 
ON [dbo].[Users] 
FOR UPDATE
  AS
    BEGIN
      INSERT INTO [Audit_Users]
      SELECT * , dbo.GetUserContext() , GETUTCDATE() , 0 FROM inserted
    END
GO
CREATE TABLE [dbo].[Users] (
    [Id]        NVARCHAR (64)  NOT NULL,
    [FirstName] NVARCHAR (255) NOT NULL,
    [LastName]  NVARCHAR (255) NOT NULL,
    [BirthDate] DATE           NOT NULL,
    [Type]      INT            NOT NULL,
    [Status]    INT            NOT NULL,
    [CreatorId] NVARCHAR (64)  NOT NULL,
    PRIMARY KEY CLUSTERED ([Id] ASC),
    CONSTRAINT [FK_Users_ToStatus] FOREIGN KEY ([Status]) REFERENCES [dbo].[StatusUsers] ([Id]),
    CONSTRAINT [FK_Users_ToCreator] FOREIGN KEY ([CreatorId]) REFERENCES [dbo].[Users] ([Id]),
    CONSTRAINT [FK_Users_ToType] FOREIGN KEY ([Type]) REFERENCES [dbo].[TypeUsers] ([Id])
);
CREATE TABLE [dbo].[Audit_Users] (
    [Id]         INT            IDENTITY (1, 1) NOT NULL,
    [UserId]     NVARCHAR (64)  NOT NULL,
    [FirstName]  NVARCHAR (255) NOT NULL,
    [LastName]   NVARCHAR (255) NOT NULL,
    [BirthDate]  DATE           NOT NULL,
    [Type]       INT            NOT NULL,
    [Status]     INT            NOT NULL,
    [CreatorId]  NVARCHAR (64)  NOT NULL,
    [ModifierId] NVARCHAR (64)  NOT NULL,
    [Date]       DATETIME       NOT NULL,
    [Deleted]    INT            NOT NULL,
    PRIMARY KEY CLUSTERED ([Id] ASC)
);

一切似乎工作得很好，当我测试在sql请求和所有这一切都工作。问题是我需要使用实体框架在我的WCF服务中调用它们。这就是麻烦开始的地方。I 通过实体使用重载方法设置CONTEXT_INFO:

 public int SaveChanges(string modifierId)
    {
        SetUserContext(modifierId);
        return base.SaveChanges();
    }

但是当base.SaveChanges();被调用，我得到:

不能在表的ModifierId列中插入NULL值"dbo.Audit_Users";列不允许为空。插入失败。语句已被终止。

这表明我丢失了CONTEXT_INFO。我调试了(添加了一个表并修改了setContext过程，这个过程用适当的值被调用)。

谢谢你的帮助，我不是数据库专家，它可能是一些非常简单的东西，但我被困在这里…

要求:

 public partial class Entities : DbContext
    {
        public Entities()
            : base("name=Entities")
        {
        }
        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            throw new UnintentionalCodeFirstException();
        }
        public virtual DbSet<Address> Addresses { get; set; }
        public virtual DbSet<Contact> Contacts { get; set; }
        public virtual DbSet<Email> Emails { get; set; }
        public virtual DbSet<File> Files { get; set; }
        public virtual DbSet<StatusUser> StatusUsers { get; set; }
        public virtual DbSet<TypeCommon> TypeCommons { get; set; }
        public virtual DbSet<TypeFile> TypeFiles { get; set; }
        public virtual DbSet<TypeUser> TypeUsers { get; set; }
        public virtual DbSet<User> Users { get; set; }
        public virtual DbSet<Workflow> Workflows { get; set; }
        public virtual int SetUserContext(string userId)
        {
            var userIdParameter = userId != null ?
                new ObjectParameter("userId", userId) :
                new ObjectParameter("userId", typeof(string));
            return ((IObjectContextAdapter)this).ObjectContext.ExecuteFunction("SetUserContext", userIdParameter);
        }
    }

创建用户:

public UserDto Create(string id, string firstName, string lastName, DateTime birthdate, string type,
    string modifierId)
{
    var userToReturn = new UserDto
    {
        Id = id,
        FirstName = firstName,
        LastName = lastName,
        Birthdate = birthdate,
        CreatorId = modifierId,
        Status = "Created",
        Type = type
    };
    using (var db = ContextFactory.GetEntities())
    {
        var user = Mapper.Map<User>(userToReturn);

        using (var transaction = new TransactionScope()) // this creates a new transaction
        {
            db.Users.Add(user);
            db.SetUserContext(modifierId);
            if (db.SaveChanges() == 1)
            {
                userToReturn = Mapper.Map<UserDto>(user);
                userToReturn.Type = type;
                userToReturn.Status = "Created";
                transaction.Complete();
            }
        }
    }
    return userToReturn;
}