“DAL.DBHelper”的类型初始值设定项引发异常。
(配置文件)

	<connectionStrings>

		<add name="Conn" connectionString="Data Source=192.168.1.109;Initial Catalog=GuoHong;Persist Security Info=True;User ID=sa password=123"/>

	</connectionStrings>

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（DBHelper）

    public class DBHelper

    {

        public static string Conn = ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;



        public static DataTable ExecuteDataTable(string sql,params SqlParameter[] para)

        {

            using(SqlConnection conn=new SqlConnection(Conn))

            {

                conn.Open();

                using(SqlCommand cmd=conn.CreateCommand())

                {

                    cmd.CommandText = sql;

                    cmd.Parameters.AddRange(para);

                    SqlDataAdapter ada = new SqlDataAdapter(cmd);

                    DataSet ds = new DataSet();

                    ada.Fill(ds);

                    return ds.Tables[0];

                }

            }

        }        

    }

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(Default.aspx.cs)

    protected void Page_Load(object sender, EventArgs e)