LINKQ问题，急啊。

为什么我写数据访问层时DashboardDataContext点不出呢？是不是要导入名称空间还是要引用什么DLL文件？第一次写linkq访问，别见怪
public const string ConnectionStringName = "DashboardConnectionString";
public static DashboardDataContext GetDashboardData()
{
var db = new DashboardDataContext(ConfigurationManager.ConnectionStrings[ConnectionStringName].ConnectionString);
return db;
}