关于Application有关问题

关于Application问题
在工程中，我建了一个类，用来写一些公共的方法，下面是用于数据库连接的一个方法。由于在类中引用不到Application，故通过参数page间接调用Application，但是在调试中存在一个问题，objPage.Application[ "DBConn "]此调用经常出错，弹出的错误提示为：Object   reference   not   set   to   an   instance   of   an   object.  
Description:   An   unhandled   exception   occurred   during   the   execution   of   the   current   web   request.   Please   review   the   stack   trace   for   more   information   about   the   error   and   where   it   originated   in   the   code.  

Exception   Details:   System.NullReferenceException:   Object   reference   not   set   to   an   instance   of   an   object.


请教各位大侠，看看问题出在哪里。附加代码如下：
public   static   SqlConnection   DBConnection(Page   objPage)
{
      SqlConnection   objConn;
      if(objPage.Application[ "DBConn "]   ==   null)
          {
                string   strConnection   =   ConfigurationSettings.AppSettings[ "SqlSvrIP "].ToString();
                objConn   =   new   SqlConnection(strConnection);
                objConn.Open();
                objPage.Application[ "DBConn "]   =   objConn;
          }
      else
          {
                objConn   =   (SqlConnection)objPage.Application[ "DBConn "];
          }
      return   objConn;
}

------解决方案--------------------------------------------------------
public static SqlConnection DBConnection(SqlConnection DBConn)
{
SqlConnection objConn;
if(DBConn == null)
{
string strConnection = ConfigurationSettings.AppSettings[ "SqlSvrIP "].ToString();
objConn = new SqlConnection(strConnection);
objConn.Open();
}
else
{
objConn =DBConn;
}
return objConn;
}
===================================================
在调用的时候
先把Application转化为SqlConnection传过去.
调用完之后在给Application从新赋值.