pass information between XXX.Aspx and XXX.Aspx.cs

1.  in XXX.aspx

 <map name="Navigation" runat="server">
      <area shape="RECT" coords="15,60,72,80" href="TEST.aspx" alt="期刊介绍" target="_New">
      <area shape="RECT" coords="81,60,138,80" href="TEST.aspx" alt="读者需知" target="_New">
      <area shape="RECT" coords="150,60,207,80" href="UserRegister.aspx" target="_New" alt="用户注册">
      <area shape="RECT" coords="219,60,276,80" href="UpdateUserProfile.aspx" target="_New"
       alt="用户信息更新">
      <area shape="RECT" coords="288,60,345,80" href="ForgetPassword.aspx" target="_New" alt="忘记密码">
      <area shape="RECT" coords="357,60,414,80" href="./PaperSubmissionProgram/PaperSubmissionPrepare.aspx"
       target="_Blank" alt="文章提交">
      <!-- http://www.dotnet247.com/247reference/msgs/42/212769.aspx -->
      <area shape="RECT" id="LogInOut" coords="422,60,479,80" href="<%=XYZ()%>" target="BottomFrame" alt="用户登录">
      <!--<area shape="rect" coords="472,24,517,37" href="javascript:open_help('/robohelp3.0/author/index.htm')"
    alt="Help" />
    -->
     </map>


2.  in XXX.aspx.cs

protected string XYZ()
  {
   string str;
   if(Session["UserName"]!=null && Session["Password"]!=null)
   {
    str="LogOut.aspx";
   }
   else
   {
    str = "LogOn.aspx";
   }

   return str;
  }
  private void Page_Load(object sender, System.EventArgs e)
  {
   // Put user code to initialize the page here
   
   if(Session["UserName"]!=null && Session["Password"]!=null)
   {
    
    Label1.Visible=true;
    Label2.Text=Convert.ToString(Session["UserName"]);
    //1.http://63.236.18.31/forum/aspPLUS.asp?M=758826&T=758826&F=36&P=1#758854
    //2.http://dotnet247.com/247reference/msgs/15/77741.aspx
    //3.http://www.dotnet247.com/247reference/msgs/42/212769.aspx
    //4.http://www.dotnetspider.com/kb/Article1188.aspx
    System.Web.UI.HtmlControls.HtmlImage IMG  = (System.Web.UI.HtmlControls.HtmlImage)Page.FindControl("IMG1");
    IMG.Attributes.Add("src", "image/TopPic1.gif");
    
   }
   else
   {
    Label1.Visible=false;
    
   }
  }