Scroll Page 表单提交后页面重新滚回原来滚动条所在位置

最新推荐文章于 2024-08-21 08:46:49 发布

转载最新推荐文章于 2024-08-21 08:46:49 发布 · 827 阅读

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#scroll #javascript #string #null

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本文介绍了一个ASP.NET页面组件ScrollPage，该组件能够保存并恢复页面的垂直和水平滚动位置，提供更好的用户体验。通过简单的配置即可实现滚动状态的持久化。

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

#region Disclaimer

/**********************************************************************

Based on presentation by Brad McCabe of Infragistics

Updated by Scott Watermasysk (http://scottwater.com)

Provided as is, with no warrenty, etc.

Please use however you see fit. Just don't ask for a VB version :)

***********************************************************************/

#endregion

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"]));

}