LinqHelper连接数据库配置
/// <summary>

     /// Linq通用数据访问类

     /// 指定TDataBase来代替后面要使用的数据上下文(指代)

     /// where：说明指代的类型

     /// new：限定必须有一个不带参数的构造函数

     /// </summary>

     /// <typeparam name="TDataBase"></typeparam>

     public class LinqHelper<TDataBase> where TDataBase : DataContext, new()

     {

         private static string connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ToString();

         TDataBase db = null;

         /// <summary>

         /// 创建数据库连接

         /// </summary>

         public LinqHelper()

         {

             db = new TDataBase();

             db.Connection.ConnectionString = connectionString;

         }