EF

1. 搭建

新搭建好的EF，当你运行程序时报：

The model backing the 'SqlServerDbContext' context has changed since the database was created. Consider using Code First Migrations to update the database 

这个时候如果你用 add-migration xxx   报如下错：

No migrations configuration type was found in the assembly 'webTest'. (In Visual Studio you can use the Enable-Migrations command from Package Manager Console to add a migrations configuration).

解决办法：去掉上下文 对象中的 : base("name=TestDb")  。执行成功后，再将代码还原。

 /// <summary>
        /// 利用App.config中配置的字符串连接数据库
        /// </summary>
        public SqlServerDbContext() : base("name=TestDb")
        {
        }

1.  插入报错：An error occurred while updating the entries. See the inner exception for de

基本是实体问题，要么主键问题，要么字段多了少了，类型不对。

2.　　报错：Object must implement IConvertible.

检查实体类型和字段是否一致