I am trying to add update panel to my sharepoint sitepage below:

I am getting the error :

Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request

I am tring to do a partial postback of webpart calendar. The problem is when i click on the next button for next month in the calender the entire page postback , i want only the calander to get it post back.

Designer code below :

<%@ Page Language="C#" masterpagefile="../_catalogs/masterpage/gmteam.master" title="DBCalendar" inherits="Microsoft.SharePoint.WebPartPages.WebPartPage, Microsoft.SharePoint, Version=, Culture=neutral, PublicKeyToken=71e9bce111e9429c" meta:progid="SharePoint.WebPartPage.Document" meta:webpartpageexpansion="full" %>
<%@ Register tagprefix="WebPartPages" namespace="Microsoft.SharePoint.WebPartPages" assembly="Microsoft.SharePoint, Version=, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>
<%@ Register tagprefix="Announcements" namespace="DashBoard.WebParts.Announcements" assembly="DashBoard, Version=, Culture=neutral, PublicKeyToken=de9581e0d9fc52c9" %>
<%@ Register tagprefix="QuickLinks" namespace="DashBoard.WebParts.QuickLinks" assembly="DashBoard, Version=, Culture=neutral, PublicKeyToken=de9581e0d9fc52c9" %>
<%@ Register tagprefix="WebParts" namespace="QuestechSystems.SharePoint.WebControls.WebParts" assembly="QuestechSystems.SharePoint.EventCalendarList, Version=, Culture=neutral, PublicKeyToken=5242205e2f823a28" %>
<asp:Content id="Content1" runat="server" contentplaceholderid="PlaceHolderMain">

<asp:UpdatePanel id="UpdatePanel1" runat="server">
<WebPartPages:SPWebPartManager runat="server" id="SPWebPartManager"></WebPartPages:SPWebPartManager>
<WebPartPages:WebPartZone id="g_07F53443D5644C878F1C29FD34C7CD3B" runat="server" title="Zone 1">
<WebParts:EventCalendarListWebPart runat="server" FirstDayOfWeek="Default" ListName="Calendar" SiteUrl="" NumDaysInEventListing="3" ShowCalendar="True" Description="Displays events in a calendar and a list." ShowListing="True" Title="Event Calendar Listing" __MarkupType="vsattributemarkup" __WebPartId="{c19a9b14-c634-4b13-a3bf-e06821d05bb4}" WebPart="true" __designer:IsClosed="false" partorder="2" id="g_c19a9b14_c634_4b13_a3bf_e06821d05bb4"></WebParts:EventCalendarListWebPart>


1 Answer 1


you might want to have a look into this blog which explains the control tree:


Both links within the article are very good in explaining the viewstate and the life cycle of an asp.net page. Hope it helps.

Kind Regards


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