C#调用DLL里的方法出问题

[w5588660]

//类DataAccess

namespace DALFactory
{
public class DataAccess
{
private Assembly _Assembly;
string _path;
public DataAccess()
{
_path =ConfigurationManager.AppSettings["WebDAL"];
_Assembly = Assembly.Load(_path);
}
public IAboutDao CreateAboutDao()
{
string className = _path + ".AboutDao";
return _Assembly.CreateInstance(className) as IAboutDao;
}
}
}

//IAboutDao接口

namespace IDAL
{
public interface IAboutDao
{
IList<AboutInfo> GetAboutContentById(string sId);
}
}

/*注意了在下面的代码要调用*/

using Model;
using IDAL;
using DALFactory;

namespace BLL
{
public class About
{
private static readonly IAboutDao dal =DataAccess.CreateAboutDao();
public IList<AboutInfo> GetAboutInfoById(string sId)
{
return dal.GetAboutContentById(sId);
}
}
}
//问题出现在这

private static readonly IAboutDao dal =DataAccess.CreateAboutDao();
错误 1 非静态的字段、方法或属性“DALFactory.DataAccess.CreateAboutDao()”要求对象引用 C:\My Documents\Visual Studio 2005\Projects\抽象三层\BLL\About.cs 13 25 BLL

请问这是怎么回事，应该怎么才能获取到DataAccess的CreateAboutDao方法

[jiezi316]

public static IList<AboutInfo> GetAboutInfoById(string sId)
{
return dal.GetAboutContentById(sId);
}

[w5588660]

兄弟，你的方法不行，问题出在DataAccess.CreateAboutDao()”要求对象引用
DLL也引用了 为什么调用不到方法呢？

[xiaomage71]

public static IAboutDao CreateAboutDao()