这是什么错误？CS0260: Missing partial modifier on declaration of type 'Conn'; another partial declaration of this type exists

[KeepOn]

cs文件代码如下：
using System;
using System.Data;
using System.Data.SqlClient;

public class Conn
{
public string ConnStr="Data Source=localhost;Initial Catalog=KONews;Persist Security Info=True;User ID=sa;Password=";
SqlConnection conn;

static Conn()
{
}

public Conn()
{
}

public void ConnOpen()
{
conn = new SqlConnection(ConnStr);
conn.Open();
}

public void ConnClose()
{
conn.Close;
conn.Dispose;
}
}

aspx文件调用时写的是
Conn conn = new Conn();
conn.ConnOpen();

结果出现错误：CS0260: Missing partial modifier on declaration of type 'Conn'; another partial declaration of this type exists
显示是Line 5: public class Conn这一行的错误
这是怎么回事？
谢谢

[jupiterII]

你是不是把这个cs文件作为一个aspx的codebehind了?
asp.net2.0中,一个aspx的codebehind class必须是partial的,这个和他的实现机制有关.