找不到类型或命名空间名称“MyPetshopDataContext”

[cwj19900302]

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

public partial class ProductShow : System.Web.UI.Page
{
MyPetshopDataContext db = new MyPetShopDataContext();
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
var categories = from c in db.Category
select new
{
c.CategoryId
c.Name
};
foreach (var category in categories )
{
ddlCategory.Items.Add(new ListItem (category .Name.ToString(),category .CategoryId.ToString()));
}
}
}
protected void dllCartegory_SelectedIndexChanged(object sender, EventArgs e)
{
Bind();
}
protected void Bind()
{
int categoryId = int Parse(ddlCategory.SelectrdValue);
var products = from p in db.Product
where p.CategoryId == categoryId select p;
gvProduct .DateSource = products ;
gvProduct.DataBind ();
}
protected void gvProduct_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
gvProduct.PageIndex = e.NewPageIndex;
Bind();
}
}



编译器错误消息: CS0246: 找不到类型或命名空间名称“MyPetshopDataContext”(是否缺少 using 指令或程序集引用?)
MyPetshopDataContext db = new MyPetShopDataContext();

请问该怎么改啊

[cwj19900302]

说要在所有事件、方法外声明MyPetShopDataContext对象db，使得该对象可在多个事件代码或方法中使用，代码如下：MyPetshopDataContext db = new MyPetShopDataContext();

上下文也没有提到MyPetshopDataContext，也没有提示怎么弄。具体该怎么改啊？我是新手，麻烦详细点

[DENQH]

MyPetshopDataContext这个是在哪个空间，你得用头上using XXXXXX