编译器错误消息: CS0122: “DAL.FormatString”不可访问，因为它受保护级别限制

编译错误 
说明: 在编译向该请求提供服务所需资源的过程中出现错误。请检查下列特定错误详细信息并适当地修改源代码。 

编译器错误消息: CS0122: “DAL.FormatString”不可访问，因为它受保护级别限制

源错误:

 

行 20: BLL.NewsLogic B_news = new BLL.NewsLogic();
行 21: BLL.BigClassLogic B_bc = new BLL.BigClassLogic();
行 22: DAL.FormatString FString = new DAL.FormatString();
行 23: 
行 24: protected void Page_Load(object sender, EventArgs e)

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;
using DAL;

public partial class web_Default2 : System.Web.UI.Page
{
  /// <summary>
  /// 实例化接口层NewsLogic类的对象
  /// </summary>
  BLL.NewsLogic B_news = new BLL.NewsLogic();
  BLL.BigClassLogic B_bc = new BLL.BigClassLogic();
  DAL.FormatString FString = new DAL.FormatString();

  protected void Page_Load(object sender, EventArgs e)
  {
  if (!Page.IsPostBack)
  {
  DataBindRepeater1();
  DataBindRepeaterBigClass();
  this.Title = "新闻系统----本系统采用ASP.NET 3.5+SQL Server 2005技术架构！";
  Session.Clear();

  }
  }


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DAL
{
  /// <summary>
  /// 字符串处理类
  /// </summary>
  public class FormatString
  {
  #region 字符串截取函数
  /// <summary>
  /// 截取字符串方法
  /// </summary>
  /// <param name="inputString">要截取的原字符串</param>
  /// <param name="len">要截取的长度</param>
  /// <returns>截取后的字符串</returns>

  public string CutString(string str1, int length)
  {
  int s = str1.Length;
  if (length <= s)
  {
  str1 = str1.Substring(0, length) + "…";
  }
  return str1;
  }
  #endregion
  }
}


  我的疑问：为什么我把FormatString定义为public类了，还是会报错呢？

你需要重新生成一下