PageRequestManagerParserErrorException with the Update Panel

I have spent quite a bit of time researching this and I cannot figure it out. So if there is anybody that has any ideas I am all ears.

I have a pretty simple site that uses a few update panels. I am developing with VS2005 on XP all the patches and using ASP.NET AJAX 1.0. Everything works perfect on my dev machine and on second beta server I have. When everything get moved to the client site they get the "PageRequestManagerParserErrorException" error on the pages with the update panel. I am not using server.transfer or respnse.write() or any other known issues. The client machine is a test box that was imaged for this app. Running Win2003 all clean and up to date in a pretty standard configuration.

I am just looking for direction: I saw some posts about response caching and machinekey but I have no idea what to look for or what to direct the sys admin to look for.

Any help would be greatly appreciated.

Craig.

Have a look here for troubleshooting tips:http://weblogs.asp.net/leftslipper/archive/2007/02/26/sys-webforms-pagerequestmanagerparsererrorexception-what-it-is-and-how-to-avoid-it.aspx

Also see this related post:http://forums.asp.net/p/1038252/1439637.aspx

Hope these help...

-Damien

Damien,

Thanks for the links. In my searching I did come accross them (and meany others). So I threw up a server outside of my network that and tried to hit the pages with an update panel again. And this time I get the error (sometimes). It was strange that I would sometimes get an error and others I wouldn't. So I installed fiddler to see what the response was like. When I get an error I notice this in the respose;

[HttpException (0x80004005): Server cannot modify cookies after HTTP headers have been sent.]
System.Web.HttpCookieCollection.Add(HttpCookie cookie) +103
System.Web.Security.RoleManagerModule.OnLeave(Object source, EventArgs eventArgs) +650
System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +92
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +64

I am using a master page that will show differnt information based on the user's role. My guess is that the injection of this error into the response is causing the problem because when it works there is no error. Unfortunatly I don't know what this means yet. Guess it's back to the internet for some studying.

If anybody has any sugestions or direction on addressing this issue I would welcome the advice.

Regards,

Craig

Got it!

This link was the answerhttp://forums.asp.net/p/1069056/1556225.aspx#1556225

I still need to read up on the issue but the answer was to set the cacheRolesInCookie=false in the web.config file. Made the change and all is good. Although, I now wonder what the impact is now on perfomance.

Craig

Paging With AJAX Using a Datalist.

I've spent a good 6 hours trying to figure this out and came up with nothing... nothing worked nor was it going to. So now I'm posting because I need HELP! I have a datalist that spits out images from a database. Simple enough... now I need only 5 of those images to display at any given time with a next and previous button to flip through all the pics as if they were thumbnails without the page reloading... so thats where ajax comes into play. My problem is that I'm still fairly new to ajax and I've already jumped into asp.net ajax. Does anybody know how I can accomplish this?

The easiest way is using UpdatePanel.

http://www.asp.net/ajax/documentation/live/overview/UpdatePanelOverview.aspx

I've looked into the updatepanel but I've never used one before. Looks interesting but i'm still confused as to how to use what i have in it to only show 5 images at a time with next and previous buttons. Can someone point me in the right direction?

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder" Runat="Server">
<asp:ScriptManager ID="ScriptManager" runat="server" />
<asp:ObjectDataSource ID="ImageObjectDataSource" runat="server" TypeName="IllumiCell.NorthOfTorontoUG.BLL.Image" OldValuesParameterFormatString="original_{0}" SelectMethod="GetImageDataByAlbumId">
<SelectParameters>
<asp:QueryStringParameter DefaultValue="0" Name="albumId" QueryStringField="albumId" Type="Int32" />
</SelectParameters>
</asp:ObjectDataSource>
<script type="text/javascript" language="javascript">
var xmlHttpRequestObject = false;

try
{
// Firefox, Opera 8.0+, Safari
xmlHttpRequestObject = new XMLHttpRequest();
}
catch (e)
{
// Internet Explorer
try
{
xmlHttpRequestObject = new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e)
{
try
{
xmlHttpRequestObject = new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e)
{
alert("Your browser does not support AJAX!");
window.location="Default.aspx";
}
}
}

function changeImage(img)
{
if (xmlHttpRequestObject)
{
var obj = document.getElementById("ViewImage");

xmlHttpRequestObject.open("GET", img);

xmlHttpRequestObject.onreadystatechange = function()
{
if(xmlHttpRequestObject.readyState == 4 && xmlHttpRequestObject.status == 200)
{
// The state is complete and the status is successful.
}
}

/*int originalHeight = obj.width;
int originalWidth = obj.height;
int panelWidth = 576;
int panelHeight;

if (originalHeight >= originalWidth)
{
panelHeight = panelWidth * (originalWidth / originalHeight);
panelWidth = originalWidth / (originalHeight / panelHeight);
}
else
{
panelWidth = panelWidth * (originalHeight / originalWidth);
panelHeight = originalHeight / (originalWidth / panelWidth);
}

obj.style.width = panelWidth + "px";
obj.style.height = panelHeight + "px";*/

obj.src = "album/" + img;
}
else
{
alert("Your browser does not support AJAX!");
window.location="Default.aspx";
}
}

function changeDescription(desc)
{
if (xmlHttpRequestObject)
{
var descObj = document.getElementById("objDesc");

xmlHttpRequestObject.open("GET", desc);

xmlHttpRequestObject.onreadystatechange = function()
{
if(xmlHttpRequestObject.readyState == 4 && xmlHttpRequestObject.status == 200)
{
// The state is complete and the status is successful.
}
}

descObj.innerHTML = desc;
}
else
{
alert("Your browser does not support AJAX!");
window.location="Default.aspx";
}
}
</script>
<div style="background-image:url('img/Header.png'); background-repeat:no-repeat; height:50px;
font-family:Verdana; text-align:center; font-size:medium; font-weight:bold; ">
<br />Photos
</div>
<center>
<asp:UpdatePanel ID="UpdatePanel" runat="server" UpdateMode="Conditional">
<ContentTemplate>

</ContentTemplate>
</asp:UpdatePanel>
<asp:Panel ID="ImageViewPanel" runat="server" Height="432px" Width="576px" BorderColor="white" BorderWidth="5px">
<asp:FormView ID="ImageFormView" runat="server" DataSourceID="ImageObjectDataSource" DataKeyNames="ImageId">
<ItemTemplate>
<img src='album/<%# Eval("AlbumId") %>/<%# Eval("ImageName") %>' id="ViewImage" alt="" />
<div id="objDesc"><%# Eval("ImageDescription") %></div>
</ItemTemplate>
</asp:FormView>
</asp:Panel>
<p /><asp:DataList ID="ImageDataList" RepeatDirection="Horizontal" RepeatColumns="5" runat="server" DataKeyField="ImageId" DataSourceID="ImageObjectDataSource">
<ItemTemplate>
<div style="padding:10px;">
<img src='album/<%# Eval("AlbumId") %>/thumb_<%# Eval("ImageName") %>' onclick="changeImage('<%# Eval("AlbumId") %>/<%# Eval("ImageName") %>'); changeDescription('<%# Eval("ImageDescription") %>')"
alt='<%# Eval("ImageDescription") %>' style="background-color:White;" />
</div>
</ItemTemplate>
</asp:DataList>
</center>
<div style="background-image:url('img/Footer.png'); background-repeat:no-repeat; height:44px;
font-family:Verdana; font-size:medium; font-weight:bold;">
</div>
</asp:Content>

Certainly you can use UpdatePanel for Ajaxifying your Page but the DataList control does not have any builtin paging feature like the GridView or DataGrid. For this you have write your own paging solution or use custom pager developed by others. Checkout the following links:

http://www.codeproject.com/useritems/SmartPager.asp
http://www.codeproject.com/aspnet/CollectionPager.asp
http://www.codeproject.com/aspnet/ASPNETPagerControl.asp

Another solution might if you are only showing pictures you can try the SlideShow of Ajax Control Toolkit.
http://www.asp.net/AJAX/Control-Toolkit/Live/SlideShow/SlideShow.aspx

I still can't figure this out... I've been all over google as well. I can't use the updatepanel... doesn't really seem to work with the datalist (i need the datalist so that i can show 5 columns). And I also need it to be ajax enabled. Does anybody know how they can take a datalist control with 5 columns... cut off the proceeding rows and make it act like a pager without a postback? My heads about to burst!

Hmm... I think I'll give silverlight a try.