鸟食轩的"SmartNavigation"补充版

关于asp.net的页面回滚后状态的保存一直是我头痛的问题.

我之前的处理方法是写一个函数来处理页面的定位问题.

这个函数也是参考了很多人的处理方法,自己再稍微处理了一下,代码如下:

Retain Events#region Retain Events
        protected void Retain()
        {
            StringBuilder saveScrollPosition = new StringBuilder ();
            StringBuilder setScrollPosition = new StringBuilder ();

            RegisterHiddenField("__SCROLLPOS", "0");


            saveScrollPosition.Append("<script language='javascript'>");
            saveScrollPosition.Append("document.body.id='MyBody';");
            saveScrollPosition.Append("function saveScrollPosition() {");
            saveScrollPosition.Append("    document.forms[0].__SCROLLPOS.value = MyBody.scrollTop;");
            saveScrollPosition.Append("}");        
            saveScrollPosition.Append("MyBody.onscroll=saveScrollPosition;");
            
            saveScrollPosition.Append("</script>");

            RegisterStartupScript("saveScroll", saveScrollPosition.ToString());


            if (Page.IsPostBack)
            {
                setScrollPosition.Append("<script language='javascript'>");
                setScrollPosition.Append("function setScrollPosition() {");
                setScrollPosition.Append("    MyBody.scrollTop = " + Request["__SCROLLPOS"] + ";");
                setScrollPosition.Append("}");
                setScrollPosition.Append("MyBody.onload=setScrollPosition;");
                setScrollPosition.Append("</script>");

                RegisterStartupScript("setScroll", setScrollPosition.ToString());
            
            }
        }

        protected void Retain(string div)
        {
            string[] divs = {div};
            Retain(divs);
        }
        protected void Retain(string[] divs)
        {
            StringBuilder saveScrollPosition = new StringBuilder ();
            StringBuilder setScrollPosition = new StringBuilder ();

            RegisterHiddenField("__SCROLLPOS", "0");
            

            saveScrollPosition.Append("<script language='javascript'>");
            saveScrollPosition.Append("document.body.id='MyBody';");
            saveScrollPosition.Append("function saveScrollPosition() {");
            saveScrollPosition.Append("    document.forms[0].__SCROLLPOS.value = MyBody.scrollTop;");
            saveScrollPosition.Append("}");
            saveScrollPosition.Append("MyBody.onscroll=saveScrollPosition;");

            saveScrollPosition.Append("function saveDivDisplay() {");
            
            foreach(string div in divs)
            {
                if ((div != null)||(div != ""))
                {
                    RegisterHiddenField("__"+div,"");
                    saveScrollPosition.Append("    document.forms[0].__"+div+".value = "+div+".style.display;");
                }
            }
            
            saveScrollPosition.Append("}");
            saveScrollPosition.Append("MyBody.onmousedown=saveDivDisplay;");
            
            saveScrollPosition.Append("</script>");

            RegisterStartupScript("saveScroll", saveScrollPosition.ToString());


            if (Page.IsPostBack)
            {
                setScrollPosition.Append("<script language='javascript'>");
                setScrollPosition.Append("function setScrollPosition() {");

                foreach(string div in divs)
                {
                    if ((div != null)||(div != ""))
                    {
                        setScrollPosition.Append("    "+div+".style.display = '" + Request["__"+div] + "';");
                    }
                }

                setScrollPosition.Append("    MyBody.scrollTop = " + Request["__SCROLLPOS"] + ";");
                setScrollPosition.Append("}");
                setScrollPosition.Append("MyBody.onload=setScrollPosition;");
                setScrollPosition.Append("</script>");

                RegisterStartupScript("setScroll", setScrollPosition.ToString());
                
            }
        }


        #endregion

用隐藏控件来保存值,但是有个问题,再回滚回来之后,页面再处理层的显示的时候会出现跳动.

看了鸟食轩的SmartNavigation系列文章,觉得非常的好用,解决了自己一直苦恼的问题,我想如果在控件里面自动循环出所有的层,然后控件呈现的时候把这些状态还原回去.
但是改了之后发现无法正常工作,估计还是自己太菜了.修改后的代码如下:

    [DefaultProperty("Text")] 
    [ToolboxData("<{0}:ClientNavigation runat=server></{0}:ClientNavigation>")] 
    public class ClientNavigation : WebControl, INamingContainer, IPostBackDataHandler 
    { 
        public ClientNavigation() : base() {} 

        Properties#region Properties 
        public int PositionTop 
        { 
            get 
            { 
                object obj = ViewState["PositionTop"]; 
                return obj == null ? 0 : (int)obj; 
            } 
            set 
            { 
                ViewState["PositionTop"] = value; 
            } 
        } 
 
        public int PositionLeft 
        { 
            get 
            { 
                object obj = ViewState["PositionLeft"]; 
                return obj == null ? 0 : (int)obj; 
            } 
            set 
            { 
                ViewState["PositionLeft"] = value; 
            } 
        } 

        public string DivDisplay
        {
            get 
            { 
                object obj = ViewState["DivDisplay"]; 
                return obj == null ? "''": (string)obj; 
            } 
            set 
            { 
                ViewState["DivDisplay"] = value; 
            } 
        }

        #endregion 
 
        protected override void Render(HtmlTextWriter writer) 
        { 
            this.RegisterClientScript(); 
            writer.AddAttribute(HtmlTextWriterAttribute.Type, "hidden"); 
            writer.AddAttribute(HtmlTextWriterAttribute.Id, this.ClientID); 
            writer.AddAttribute(HtmlTextWriterAttribute.Name, this.ClientID); 
            writer.AddAttribute(HtmlTextWriterAttribute.Value,string.Format("{0}:{1}:{2}", this.PositionTop,this.PositionLeft,this.DivDisplay)); 
            //writer.AddAttribute(HtmlTextWriterAttribute.Value,string.Format("{0}:{1}", this.PositionTop,this.PositionLeft)); 
            writer.RenderBeginTag(HtmlTextWriterTag.Input); 
            writer.RenderEndTag(); 
        } 
 


        Client Script#region Client Script 
        private void RegisterClientScript() 
        { 
            const string REGISTER_KEY = "__ClientNavigate586787__"; 
            string strScript = @" 
            <script language=""javascript""> 
            window.attachEvent('onload', CLN_ClientNavigation); 
            function CLN_ClientNavigation() 
            {{ 
                var scrollTop = {0}; 
                var scrollLeft = {1}; 
                var scrollCount = 0; 
                var divdisplay = {2};    

                var dis = divdisplay.split('$$$');                                    
                
                do 
                {{ 
                    scrollCount ++; 
                    window.scrollTo(scrollLeft, scrollTop); 
                }} 
                while(document.body.scrollTop < scrollTop && scrollCount < 10 ); 
                
                var divs = document.getElementsByTagName('div');
                for(i=0;i<divs.length;i++)
                {{
                    if (dis[i+1] != null)
                    divs[i].style.cssText = dis[i+1];
                }}
            }} 
            document.body.onscroll = function() 
            {{ 
                var body = document.body; 
                
                var dis = ' ';
                var divs = document.getElementsByTagName('div');
                
                for(i=0;i<divs.length;i++) 
                {{
                    
                    dis = dis + '$$$' + divs[i].style.cssText;
                }}
                document.all.{3}.value = body.scrollTop + ':' + body.scrollLeft+ ':' + dis; 
                
            }} 
    
    


            </script>"; 


            if ( !this.Page.IsStartupScriptRegistered(REGISTER_KEY) ) 
            { 
                strScript = String.Format(strScript, this.PositionTop, this.PositionLeft, this.DivDisplay, this.ClientID); 
                //strScript = String.Format(strScript, this.PositionTop, this.PositionLeft, this.ClientID); 
                this.Page.RegisterStartupScript(REGISTER_KEY, strScript); 
            } 
        } 
        #endregion 
 
        IPostBackDataHandler interface#region IPostBackDataHandler interface 

        public void RaisePostDataChangedEvent() 
        { 
            // TODO:  Add ClientNavigation.RaisePostDataChangedEvent implementation 
        } 


        public bool LoadPostData(string postDataKey, NameValueCollection postCollection) 
        { 
            bool modify = false; 
            string postData = postCollection[postDataKey]; 
            if ( !StringHelper.IsEmpty(postData) ) 
            { 
                string [] topleft = postData.Split(new char [] {':'}); 
                int iPositionTop = int.Parse(topleft[0]); 
                int iPostionLeft = int.Parse(topleft[1]); 
                string sDiv = topleft[2];
                if ( iPositionTop != this.PositionTop ) 
                { 
                    this.PositionTop = iPositionTop; 
                    modify |= true; 
                } 
                if ( iPostionLeft != this.PositionLeft ) 
                { 
                    this.PositionLeft = iPostionLeft; 
                    modify |= true; 
                } 
                if ( sDiv != this.DivDisplay)
                {
                    this.DivDisplay = sDiv;
                    modify |= true;
                }
            } 
            return modify; 
        } 

        #endregion 
    } 

不知道是否有更好的解决方法.