asp.net c#在updatepanel中支持滚动条记忆功能

在非ajax页面中,只要在page上设置 MaintainScrollPositionOnPostback="true" 即可进行记忆滚动条位置.  但是在ajax中,这个功能却不能正确工作了,那么我们应当如何让div自动维护滚动条位置呢?
  首先在页面上增加 asp:panel控件 ,然后在aspx.cs后台 加入以下方法:
  [c#]
  protected void DoMaintainScrollPositionForAjax(UpdatePanel updatePanel,Panel panel)
  {
  StringBuilder sb = new StringBuilder();
  sb.AppendLine(@"function Panel_SaveScrollPosition(PanelID){
  if(document.getElementById(PanelID)!=null){
  document.getElementById(PanelID+'_ScrollPosX').value = document.getElementById(PanelID).scrollLeft;
  document.getElementById(PanelID+'_ScrollPosY').value = document.getElementById(PanelID).scrollTop;}}
  function Panel_RestoreScrollPosition(PanelID){
  if(document.getElementById(PanelID)!=null){
  document.getElementById(PanelID).scrollLeft = document.getElementById(PanelID+'_ScrollPosX').value;
  document.getElementById(PanelID).scrollTop = document.getElementById(PanelID+'_ScrollPosY').value;}}");
  ScriptManager.RegisterClientScriptBlock(updatePanel, panel.GetType(), "PanelScrollFunction", sb.ToString(), true);
  HiddenField x = new HiddenField();
  x.ID = panel.ClientID + "_ScrollPosX";
  x.ClientIDMode = panel.ClientIDMode;
  panel. Controls.Add(x);
  HiddenField y = new HiddenField();
  y.ID = panel.ClientID + "_ScrollPosY";
  y.ClientIDMode = panel.ClientIDMode;
  panel. Controls.Add(y);
  string sScript = "Panel_SaveScrollPosition('" + panel.ClientID + "');";
  ScriptManager.RegisterOnSubmitStatement(updatePanel, panel.GetType(), panel.ID + "_SavePanelScroll", sScript);
  if (Page.IsPostBack)
  {
  x.Value = Page.Request.Form[x.ClientID];
  y.Value = Page.Request.Form[y.ClientID];
  sScript = "Panel_RestoreScrollPosition('" + panel.ClientID + "');";
  ScriptManager.RegisterStartupScript(updatePanel, panel.GetType(), panel.ID + "_SetPanelScroll", sScript, true);
  }
  }
  protected void DoMaintainScrollPositionForAjax(UpdatePanel updatePanel,Panel panel)
  {
  StringBuilder sb = new StringBuilder();
  sb.AppendLine(@"function Panel_SaveScrollPosition(PanelID){
  if(document.getElementById(PanelID)!=null){
  document.getElementById(PanelID+'_ScrollPosX').value = document.getElementById(PanelID).scrollLeft;
  document.getElementById(PanelID+'_ScrollPosY').value = document.getElementById(PanelID).scrollTop;}}
  function Panel_RestoreScrollPosition(PanelID){
  if(document.getElementById(PanelID)!=null){
  document.getElementById(PanelID).scrollLeft = document.getElementById(PanelID+'_ScrollPosX').value;
  document.getElementById(PanelID).scrollTop = document.getElementById(PanelID+'_ScrollPosY').value;}}");
  ScriptManager.RegisterClientScriptBlock(updatePanel, panel.GetType(), "PanelScrollFunction", sb.ToString(), true);
  HiddenField x = new HiddenField();
  x.ID = panel.ClientID + "_ScrollPosX";
  x.ClientIDMode = panel.ClientIDMode;
  panel. Controls.Add(x);
  HiddenField y = new HiddenField();
  y.ID = panel.ClientID + "_ScrollPosY";
  y.ClientIDMode = panel.ClientIDMode;
  panel. Controls.Add(y);
  string sScript = "Panel_SaveScrollPosition('" + panel.ClientID + "');";
  ScriptManager.RegisterOnSubmitStatement(updatePanel, panel.GetType(), panel.ID + "_SavePanelScroll", sScript);
  if (Page.IsPostBack)
  {
  x.Value = Page.Request.Form[x.ClientID];
  y.Value = Page.Request.Form[y.ClientID];
  sScript = "Panel_RestoreScrollPosition('" + panel.ClientID + "');";
  ScriptManager.RegisterStartupScript(updatePanel, panel.GetType(), panel.ID + "_SetPanelScroll", sScript, true);
  }
  }
  通过以下方法在aspx.cs调用即可
  [c#]
  protected void Page_Load(object sender, EventArgs e)
  {
  DoMaintainScrollPositionForAjax(this.UpdatePanel1, Panel1);
  }
  protected void Page_Load(object sender, EventArgs e)
  {
  DoMaintainScrollPositionForAjax(this.UpdatePanel1, Panel1);
  }