linq中的插入数据，应该调用什么方法？

/// <summary>
///
/// 更新商品
/// </summary>
/// <param name="good"></param>
public static void UpdateGood(Good good)
{
using (GoosDBDataContext dataContext = new GoosDBDataContext())
{
//查出要更新的商品
Good data = dataContext.Good.Where(item => item.GoodsId == good.GoodsId).SingleOrDefault();
//商品名字处理
data.GoodsName = good.GoodsName;
//商品类型外键处理
data.GoodsType = dataContext.GoodsType.Where(item => item.TypeId == good.TypeId).SingleOrDefault();
data.Price = good.Price;
//商品单位外键处理
data.GoodsUnit = dataContext.GoodsUnit.Where(item => item.UnitId == good.UnitId).SingleOrDefault();
data.ProduceDate = good.ProduceDate;

//提交更新
dataContext.SubmitChanges();
}
}
/// <summary>
/// 添加商品方法
/// </summary>
/// <param name="good"></param>
public static void AddGood(Good good)
{
using (GoodSys.Models.GoosDBDataContext dataContext = new GoosDBDataContext()) {

//到这里写不下去了！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！1
Good data = good;



}
}