添加文章，需要用到一个类DataSet，怎样添加引用？
要使用类SqlData下面的方法GetDataSet()

新建了个文件夹App_code，下面放有SqlData.cs
编译的时候提示错误:未能找到类型或命名空间名称“SqlData”(是否缺少 using 指令或程序集引用?)
怎样引用这个类呢？
引用下面没办法添加啊。


Add_News.aspx.cs

C# code

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.SqlClient;namespace blog.Backstage.Users{    public partial class Add : System.Web.UI.Page    {        SqlData mydata = new SqlData();        int cbox;        string ID;        protected void Page_Load(object sender, EventArgs e)        {            if (Session["UserName"] == null)            {                Response.Redirect("~/index.aspx");            }            string sql = "select * from tb_Blog where UserName='" + Session["UserName"] + "'";            DataSet mydataset = mydata.GetDataSet(sql, "tb_Blog");            DataRowView rowview = mydataset.Tables["tb_Blog"].DefaultView[0];            ID = rowview["BlogID"].ToString();            this.TextBox2.Text = Session["UserName"].ToString();            string sqlstr = "select * from ST_Class";            SqlConnection mycon = new SqlConnection(ConfigurationManager.AppSettings["conStr"]);            SqlCommand mycom = new SqlCommand(sqlstr, mycon);            mycon.Open();            SqlDataReader dr = mycom.ExecuteReader();            //判断是否有数据            while (dr.Read())            {                DropDownList1.Items.Add(new ListItem(dr["ST_c_name"].ToString(), dr["ST_c_id"].ToString()));            }            mycon.Close();        }        protected void btnAdd_Click(object sender, EventArgs e)        {            string ID;            string sqlstr = "select * from tb_Blog where UserName='" + Session["UserName"] + "'";            DataSet mydataset = mydata.GetDataSet(sqlstr, "tb_Blog");            DataRowView rowview = mydataset.Tables["tb_Blog"].DefaultView[0];            ID = rowview["BlogID"].ToString();            //创建插入新文章信息的Sql语句            string com = "Insert into ST_news(ST_n_title,ST_n_author,ST_n_key,ST_n_content,ST_n_iscmd,ST_c_id,BlogID) values('" + this.txtSubject.Text + "','" + this.Session["UserName"].ToString() + "','" + this.TextBox1.Text + "','" + this.article_context.Text.ToString() + "','" + cbox + "','" + this.DropDownList1.SelectedValue + "','" + ID + "')";            //调用公共类中的ExceSQL方法，返回一个布尔值            bool add = mydata.ExceSQL(com);            if (add)            {                Response.Write("<script language=javascript>alert('文章添加成功!');location='ArticleManage.aspx'</script>");            }            else            {                Response.Write("<script language=javascript>alert('文章添加失败！');location='javascript:history.go(-1)'</script>");            }        }    }}

[解决办法]
检查下App_Code下的SqlData类的命名空间是不是blog.Backstage.Users，如果不是，加上对那个命名空间的引用。例如SqlData的命名空间是aaa,则在Add这个类中加上：using aaa;