Solved

Maintain scrolling in Panel after postback

Posted on 2008-06-18
10
4,208 Views
Last Modified: 2012-05-05
I have Panel with some control in it. At the very bottom of panel, I have checkbox which has Autopost=True.
When I click on checkbox, Panel takes me to first control at the top in the panel. It does not maintain its position.
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        &nbsp;
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
    </div>
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <asp:Panel ID="Panel1" runat="server" Height="184px" ScrollBars="Vertical" Style="z-index: 100;
                            left: 0px; position: absolute; top: 0px" Width="376px">
                            <asp:TextBox ID="TextBox1" runat="server" Style="z-index: 100; left: 16px; position: absolute;
                                top: 24px"></asp:TextBox>
                            <asp:TextBox ID="TextBox2" runat="server" Style="z-index: 101; left: 16px; position: absolute;
                                top: 64px"></asp:TextBox>
                            <asp:TextBox ID="TextBox3" runat="server" Style="z-index: 102; left: 16px; position: absolute;
                                top: 104px"></asp:TextBox>
                            <asp:TextBox ID="TextBox4" runat="server" Style="z-index: 103; left: 16px; position: absolute;
                                top: 144px"></asp:TextBox>
                            <asp:TextBox ID="TextBox5" runat="server" Style="z-index: 104; left: 120px; position: absolute;
                                top: 280px"></asp:TextBox>
                            <asp:CheckBox ID="CheckBox1" runat="server" AutoPostBack="True" Style="z-index: 106;
                                left: 8px; position: absolute; top: 280px" />
                        </asp:Panel>
            </ContentTemplate>
        </asp:UpdatePanel>
    </form>
</body>
</html>

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Question by:siddiqishahid
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10 Comments
 
LVL 16

Expert Comment

by:burakiewicz
ID: 21814174
you can store the position of the panel in a hiddenfield and on the page load reset the position with javascript
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Author Comment

by:siddiqishahid
ID: 21814371
Thanks for your reply. Can you give me sample code?

Thanks.
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LVL 16

Expert Comment

by:burakiewicz
ID: 21814790
javascript is first,  on your panel add onscroll="SaveScrollPosition();"

this is c# code but should be close to the same in VB
put this in your pageload, the datetime now is added so the id will be unique
ClientScript.RegisterStartupScript(this.GetType(), "RestorePosition" + DateTime.Now.Ticks, "RestoreScrollPosition()", true);
           
put this in the page or a sepereate js file
<script type="text/javascript">
    function SaveScrollPosition()
    {
        pnl=document.getElementById('Panel1')
        hdn=document.getElementById('hdnScrollPosition')
        hdn.value=pnl.scrollTop;
    }
    function RestoreScrollPosition()
    {
        pnl=document.getElementById('Panel1')
        hdn=document.getElementById('hdnScrollPosition')
        pnl.scrollTop=hdn.value;
    }
    </script>

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LVL 16

Expert Comment

by:burakiewicz
ID: 21814811
actually you will need to use
ScriptManager.RegisterStartupScript(this.UpdatePanel1, this.UpdatePanel1.GetType(), "RestorePosition" + DateTime.Now.Ticks, "RestoreScrollPosition()", true);
0
 

Author Comment

by:siddiqishahid
ID: 21815359
I am getting following error
"Conversion from string "RestorePosition" to type 'Double' is not valid."

It worked fine and got expected when I added .ToString  after DateTime.Now.Ticks, in following script,

ScriptManager.RegisterStartupScript(this.UpdatePanel1, this.UpdatePanel1.GetType(), "RestorePosition" + DateTime.Now.Ticks.ToString, "RestoreScrollPosition()", true);

Is that OK?

I am also getting following error in javascript but i got desired result.
Line: 93
Char: 24
Error: Expected ';'
Code:0

I did viewsource and tried to locate that error but could not figure out? Any suggestions?

Thanks.

 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>
	Untitled Page
</title>
    <script type="text/javascript">
    function SaveScrollPosition()
    {
        pnl=document.getElementById('Panel1');
        hdn=document.getElementById('hdnScrollPosition');
        hdn.value=pnl.scrollTop;
    }
    function RestoreScrollPosition()
    {
        pnl=document.getElementById('Panel1');
        hdn=document.getElementById('hdnScrollPosition');
        pnl.scrollTop=hdn.value;
    }
    </script>
</head>
<body>
    <form name="form1" method="post" action="Default.aspx" id="form1">
<div>
<input type="hidden" name="__EVENTTARGET" id="__EVENTTARGET" value="" />
<input type="hidden" name="__EVENTARGUMENT" id="__EVENTARGUMENT" value="" />
<input type="hidden" name="__LASTFOCUS" id="__LASTFOCUS" value="" />
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUKMTYzMjc5MjI4MmQYAQUeX19Db250cm9sc1JlcXVpcmVQb3N0QmFja0tleV9fFgIFCUNoZWNrQm94MQUJQ2hlY2tCb3gywOFFxJDMSYQyMA8nWgwm1o3aeGQ=" />
</div>
 
<script type="text/javascript">
<!--
var theForm = document.forms['form1'];
if (!theForm) {
    theForm = document.form1;
}
function __doPostBack(eventTarget, eventArgument) {
    if (!theForm.onsubmit || (theForm.onsubmit() != false)) {
        theForm.__EVENTTARGET.value = eventTarget;
        theForm.__EVENTARGUMENT.value = eventArgument;
        theForm.submit();
    }
}
// -->
</script>
 
 
<script src="/BPXA/WebResource.axd?d=1SnFzSJnzo-c1BMcPfq1rQ2&amp;t=633407563850353049" type="text/javascript"></script>
 
 
<script src="/BPXA/ScriptResource.axd?d=YvPGwM0clA7GDcymQg_2lS1jr8yv_CqgZiHkDGYZoy_kQ2XQDfR0y7ZQ8QMgoR5bhvDBaTzX7J1TzRVeStIA1cDL_LaU12JE3GVoX6us6G01&amp;t=633413469343099995" type="text/javascript"></script>
<script src="/BPXA/ScriptResource.axd?d=YvPGwM0clA7GDcymQg_2lS1jr8yv_CqgZiHkDGYZoy_kQ2XQDfR0y7ZQ8QMgoR5bhvDBaTzX7J1TzRVeStIA1VjFkDNP7vVJqyJtK-2130Sp7uREkT-EisZrNPtG6IjS0&amp;t=633413469343099995" type="text/javascript"></script>
        
        <div>
            &nbsp;<script type="text/javascript">
//<![CDATA[
Sys.WebForms.PageRequestManager._initialize('ScriptManager1', document.getElementById('form1'));
Sys.WebForms.PageRequestManager.getInstance()._updateControls(['tUpdatePanel1'], [], [], 90);
//]]>
</script>
 
          
        </div>
        <div id="UpdatePanel1">
	
            <div id="Panel1" onscroll="SaveScrollPosition();" style="height:184px;width:376px;overflow-y:scroll;z-index: 100;
                left: 0px; position: absolute; top: 0px">
		
                <input name="TextBox1" type="text" id="TextBox1" style="z-index: 100; left: 16px; position: absolute;
                    top: 24px" />
                <input name="TextBox2" type="text" id="TextBox2" style="z-index: 101; left: 16px; position: absolute;
                    top: 64px" />
                <input name="TextBox3" type="text" id="TextBox3" style="z-index: 102; left: 16px; position: absolute;
                    top: 104px" />
                <input name="TextBox4" type="text" id="TextBox4" style="z-index: 103; left: 16px; position: absolute;
                    top: 144px" />
                <input name="TextBox5" type="text" id="TextBox5" style="z-index: 104; left: 120px; position: absolute;
                    top: 280px" />
                <span style="z-index: 105;
                    left: 8px; position: absolute; top: 280px"><input id="CheckBox1" type="checkbox" name="CheckBox1" onclick="javascript:setTimeout('__doPostBack(\'CheckBox1\',\'\')', 0)" /></span>
                <input name="TextBox6" type="text" id="TextBox6" style="z-index: 106; left: 32px; position: absolute;
                    top: 440px" />
                <input name="TextBox7" type="text" id="TextBox7" style="z-index: 107; left: 32px; position: absolute;
                    top: 472px" />
                <span style="z-index: 109;
                    left: 208px; position: absolute; top: 440px"><input id="CheckBox2" type="checkbox" name="CheckBox2" onclick="javascript:setTimeout('__doPostBack(\'CheckBox2\',\'\')', 0)" /></span>
                    
            
	</div>
            
</div>
     
        <input type="hidden" id="hdnScrollPosition">
    
<div>
 
	<input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="/wEWCgLy0f6ODALs0bLrBgLs0fbZDALs0Yq1BQLs0e58AuzRgtgJAoLk17sJAuzRxsYPAuzR2qEIAv/j17sJnVn4KOJjxRDepINYarK8KGmDapY=" />
</div>
 
<script type="text/javascript">
<!--
RestoreScrollPosition()Sys.Application.initialize();
// -->
</script>
</form>
</body>
</html>

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Accepted Solution

by:
burakiewicz earned 250 total points
ID: 21815411
yeah that is fine, in C# it must auto convert it
you need a ; after the RestoreScrollPosition(),
ScriptManager.RegisterStartupScript(this.UpdatePanel1, this.UpdatePanel1.GetType(), "RestorePosition" + DateTime.Now.Ticks.ToString, "RestoreScrollPosition();<----------", true);

so use this
ScriptManager.RegisterStartupScript(this.UpdatePanel1, this.UpdatePanel1.GetType(), "RestorePosition" + DateTime.Now.Ticks.ToString, "RestoreScrollPosition();", true);

0
 
LVL 16

Expert Comment

by:burakiewicz
ID: 21815424
sorry i forgot it in my code
0
 

Author Comment

by:siddiqishahid
ID: 21815904
It works perfectly fine if I put alert script in following function,

function RestoreScrollPosition()
    {
       alert('anything');
        pnl=document.getElementById('Panel1')
        hdn=document.getElementById('hdnScrollPosition')
        pnl.scrollTop=hdn.value;
    }

if I put alert it perfectly fine. I am surprise what alert can make difference?

Thanks.
0
 
LVL 16

Expert Comment

by:burakiewicz
ID: 21815987
try adding the ; to all the items-- dangit
but not sure why it would work with an alert in there
function RestoreScrollPosition()
    {
       pnl=document.getElementById('Panel1');
        hdn=document.getElementById('hdnScrollPosition');
        pnl.scrollTop=hdn.value;
    }
0
 

Author Comment

by:siddiqishahid
ID: 21816917
It has been fixed now by adding few lines in procedures. Thanks for your help.
function SaveScrollPosition()
        {  
            window.setTimeout("SetNow('" + document.getElementById("myHidden").innerHtml + "')",2000);
            pnl=document.getElementById('Panel1');
            hdn=document.getElementById('hdnScrollPosition');
            hdn.value=pnl.scrollTop;
        }
       
        function RestoreScrollPosition()
        {    
            document.getElementById("myHidden").innerHtml = document.getElementById("Panel1").scrollTop;        
            pnl=document.getElementById('Panel1');
            hdn=document.getElementById('hdnScrollPosition');        
            pnl.scrollTop=hdn.value;
        }
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