Scroll Page 表单提交后页面重新滚回原来滚动条所在位置

作者scottwater
原文地址:http://scottwater.com/articles/ScrollPage
感谢scottwater先生!
我做了一点修改,使其支持横向滚动条位置的记忆
Disclaimer

using System;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using System.Web.UI;

namespace ShangGu.XaTaxi.Components
{
    
/// <summary>
    
/// Summary description for ScrollPage.
    
/// </summary>

    public class ScrollPage : System.Web.UI.Page
    
{
        
public ScrollPage()
        
{

        }


        
private bool _useScrollPersistence = true;
        
/// <summary>
        
/// There could be PostBack senarios where we do not want to remember the scroll position. Set this property to false
        
/// if you would like the page to forget the current scroll position
        
/// </summary>

        public bool UseScrollPersistence
        
{
            
get {return this._useScrollPersistence;}
            
set {this._useScrollPersistence = value;}
        }


        
private string _bodyID;
        
/// <summary>
        
/// Some pages might already have the ID attribute set for the body tag. Setting this property will not render the ID or change
        
/// the existing value. It will simply update the javascript written out to the browser.
        
/// </summary>

        public string BodyID
        
{
            
get {return this._bodyID;}
            
set {this._bodyID = value;}
        }



        
//Last chance. Do we want to maintain the current scroll position
        protected override void OnPreRender(EventArgs e)
        
{
            
if(UseScrollPersistence)
            
{
                RetainScrollPosition();
            }

            
base.OnPreRender (e);
        }
        

        
protected override void Render(HtmlTextWriter writer)
        
{
            
//No need processing the HTML if the user does not want to maintain scroll position or already has
            
//set the body ID value
            if(UseScrollPersistence)
            
{
                TextWriter tempWriter 
= new StringWriter();
                
base.Render(new HtmlTextWriter(tempWriter));
                
if(BodyID == null)
                
{
                    writer.Write(Regex.Replace(tempWriter.ToString(),
"<body","<body id="thebody" ",RegexOptions.IgnoreCase));
                }

                
//=++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                
//
                
//2004-9-16 武眉博 修正了因BodyID不空时造成javascript错误的bug
                
//
                
//=++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                else
                
{
                    writer.Write(Regex.Replace(tempWriter.ToString(),
"<body","<body id=""+BodyID+"",RegexOptions.IgnoreCase));

                }

            }

            
else
            
{
                
base.Render(writer);
            }

        }


        
//=++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
        
//
        
//2004-9-20 武眉博 增加了隐藏文本域"__SCROLLPOS_LEFT",以增加对横向滚动条位置的记忆功能
        
//
        
//=++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
        private static string saveScrollPosition = "<script language='javascript'>function saveScrollPosition() {{document.forms[0].__SCROLLPOS_TOP.value = {0}.scrollTop;document.forms[0].__SCROLLPOS_LEFT.value = {0}.scrollLeft ;}}{0}.onscroll=saveScrollPosition;</script>";
        
private static string setScrollPosition = "<script language='javascript'>function setScrollPosition() {{{0}.scrollTop ="{1}"; {0}.scrollLeft  ="{2}"}}{0}.onload=setScrollPosition;</script>";

        
//Write out javascript and hidden field
        private void RetainScrollPosition()
        
{
            RegisterHiddenField(
"__SCROLLPOS_TOP""0");
            RegisterHiddenField(
"__SCROLLPOS_LEFT""0");
            
string __bodyID = BodyID == null ? "thebody" : BodyID;
            RegisterStartupScript(
"saveScroll"string.Format(saveScrollPosition,__bodyID));

            
if(Page.IsPostBack)
            
{
                RegisterStartupScript(
"setScroll"string.Format(setScrollPosition,__bodyID, Request.Form["__SCROLLPOS_TOP"],Request.Form["__SCROLLPOS_LEFT"]));
            }

        }

    }


}

posted on 2004-09-20 13:55  活靶子.Net  阅读(9121)  评论(15编辑  收藏  举报

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