CREATE TABLE [dbo].[User] (
    [ID] int IDENTITY(1,1) NOT NULL,
    [Name] nvarchar(max)  NOT NULL,
    [Blog_ID] int  NOT NULL
);
GO

-- Creating table 'Blog'
CREATE TABLE [dbo].[Blog] (
    [ID] int IDENTITY(1,1) NOT NULL,
    [Name] nvarchar(max)  NOT NULL,
    [UserId] int  NOT NULL
);
GO

-- Creating table 'Post'
CREATE TABLE [dbo].[Post] (
    [ID] int IDENTITY(1,1) NOT NULL,
    [Title] nvarchar(max)  NOT NULL,
    [Content] nvarchar(max)  NOT NULL,
    [BlogId] int  NOT NULL,
    [Blog_ID] int  NOT NULL
);
GO

-- Creating table 'Comment'
CREATE TABLE [dbo].[Comment] (
    [ID] int IDENTITY(1,1) NOT NULL,
    [Title] nvarchar(max)  NOT NULL,
    [Content] nvarchar(max)  NOT NULL,
    [PostId] int  NOT NULL,
    [Post_ID] int  NOT NULL
);
GO

[ForeignKey("tid")]
        public AdDisplayType DisplayType
        {
            get;
            set;
        }

        public int tid { get; set; }

------解决方案--------------------

你还记得你建立这个东西的时候，那个向导页不， 下面有小的选项框“在模型中加入外键列”，你勾选的他，自然EF就生成了他，这是你自己选择滴。咋又怪到EF头上了