Question

找不到类型或命名空间名称“News”(是否缺少 using 指令或程序集引用?)

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

public partial class houtai_wenzhanglist : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void Button1_Click(object sender, EventArgs e)
{

}
protected void down()
{
News wenzhang = new News(); //在此地出现错误
DataTable dt = wenzhang.GetList();
for (int j = 0; j < dt.Rows.Count; j++)
{
DataRowView drv = dt.DefaultView[j];
//判断长度
if (drv[1].ToString().Length > 18)
{
drv[1] = drv[1].ToString().Substring(0, 18) + "...";

}
}
GridView1.DataSource = dt;
GridView1.DataBind();
}
protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
this.GridView1.PageIndex = e.NewPageIndex;
down();
}
}

Answer 1

缺少 using 指令或程序集引用
News是一个自定义类型，有自己的命名空间XXX，如果这个类在单独的项目中，那你首先要添加对该类程序集的引用，

调用的方式有两种：1.XXX.News wenzhang = new XXX.News();
2.Using XXX; News wenzhang = new News();

namespace XXX
{
public class News
{

}
}

Answer 2

添加News这个类的程序集的引用