State Management :: ViewState Returning Null On Postback?
Apr 18, 2010
Im currently experincing some difficulties with the viewState. The scenario is that i have a datagrid that has a column of buttons that when pressed will store a value in the viewState. I have already done this on one occasion in the same page, but for some reason the second item in the view state is always returning null, even when i hardcode in a number in before the postback. Im at a loss as to why this is happening, anyone expericened this and know what is wrong.
EDIT: Ive found out the cause, Its due to when you click a button in a data grid it does the postback code first, then fires the event handler, so of course the view state would be empty as it is coded to be set in the event handler for the button click. Is there any way to avoid that? So the event code is fired before the postback code?
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Apr 29, 2010
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May 3, 2010
I am creating a simple string of values that get added to a label after a post back. I am setting the values thorugh ViewState. However, my appended values do not get updated until AFTER the 2nd postback. Example:
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What I am I missing? Code Below.
.ascx - I left out inherits and codebehind
[Code]....
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Feb 5, 2011
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[Code]....
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Oct 9, 2010
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[Code]....
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Jan 11, 2011
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Apr 30, 2010
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Aug 24, 2010
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Jun 4, 2010
I've got a weird problem with a NullReferenceException on a high traffic website my company hosts. The exceptions are logged with full stack-traces but I am unable to reproduce it.The exception occurs a couple of times a day, for different users, and it's a NullReferenceException thrown in the code block below:
protected void Page_Load(object sender, EventArgs e)
{
...
if (!Page.IsPostBack)
{
...
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...
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Does anyone know how this could happen, or any other reason why a NullReferenceException would be thrown on the above line?
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at MyCompany.MyApplication.Appliance.Page_Load(Object sender, EventArgs e) in C:Documents and SettingsshellamaMy DocumentsMyApplicationAppliance.aspx.cs:line 54
at System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e)[code]....
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May 20, 2010
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[Code]....
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Oct 25, 2010
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Sep 16, 2010
I am developing a a web application of a general store where the operator has to enter the things what customer has purchased. Like daily usage item,or anything. So I have form in which I first ask how much item u wannt to register...(if he has 20-30 number of items then operator will enter 20-30 then in gridview 20-30 item are opened. With bind dropdownbox containing name of item ,then textboxs containing mrp, value, stock avail of that item. Here is the link for demo. [URL]. Problem is suppose the operator enter the value above 20, then viewstate size id about 1.50Mb that's too heavy.
[Code]....
Here is .cs code
[Code]....
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Jan 31, 2011
I stored a list<mytype> object in a viewstate. Type of list<mytype> comes from a public structure which is defined at page.
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Public struct mytype
{....}
Page_load()
{ list<mytype> obj = new list<mytype>();
viewstate["mystate"]=obj
}
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May 27, 2010
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Jan 3, 2011
i want to store IQueryable value to ViewState. my code is as below:
Private
Property _Query()
As IQueryable
Get
Return
CType(ViewState("_Query"), IQueryable)
End
Get
Set(ByVal value
As IQueryable)
ViewState("_Query") = value
End
Set
but when i run my page i get following error:
Type 'System.Data.Linq.DataQuery`1[[DynamicQueries.VW_EmployeeProfile_Filter, DynamicQueries, ersion=1.0.0.0, Culture=neutral, PublicKeyToken=null]]' in Assembly 'System.Data.Linq, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' is not marked as serializable
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Private Shared _Query As IQueryable
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Feb 28, 2011
As you know viewstate can recognize as a vulnarable item if we do not encrype it I know how to encrype the viewstate that I define in a web page but my problem start from here I downloaded a software which help you to exract the unencrypted viewstate of every website the link of that software is as follow:
[URL]
but when I make even empty page without viewstate ,this program can extract the viewstae of my page but if check some website like google ,yahoo,amazoon
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Jun 4, 2010
I have an application that I am working on. We are experiencing odd outages daily. The outages actually bring down the Virtual Servers (web farm of 4 VMs). The last odd metric before VM becomes inaccessible is that disk I/O is at 100%. While discussing this with the client, an idea was thrown out that I wouldn't have considered because I have never heard of such a thing. The idea was that our immense ViewState (yes I will be working on reducing that in the next release) overwhelmed the server or something and the server needed to start writing the ViewState to a file in a temporary folder somewhere. The thought was that when the server started to get overwhelmed, it would have to queue requests and would run out of memory and need to start using disk.
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Dec 29, 2010
In our control environment, we've started, somewhat intermittently, getting:
Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.
on our website.It also suggests:
Source Error: The source code that generated this unhandled exception can only be shown when compiled in debug mode. To enable this, please follow one of the below steps, then request the URL:
1. Add a "Debug=true" directive at the top of the file that generated the error. Example:
<%@ Page Language="C#" Debug="true" %> or:
2) Add the following section to the configuration file of your application:
<configuration>
<system.web>
<compilation debug="true"/>
</system.web>
</configuration>
Note that this second technique will cause all files within a given application to be compiled in debug mode. The first technique will cause only that particular file to be compiled in debug mode.
Important: Running applications in debug mode does incur a memory/performance overhead. You should make sure that an application has debugging disabled before deploying into production scenario.
We already have compilation debug as true. We have upgraded our website to ASP.NET 4.0, although our middle tier components are still at 3.5. As we do in out production machine configs (which are using ASP.NET 3.5) we have
<section type="System.Web.Configuration.MachineKeySection, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=abcabc123123" allowDefinition="MachineToApplication"/>
we also have one in the new .NET 4.0 machine.config:
<section type="System.Web.Configuration.MachineKeySection, System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=abcabc123123" allowDefinition="MachineToApplication" />
This control environment is not in a server farm. Why is it suggesting that I turn on debug, when it's already on. Why isn't it showing me my source code?
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Mar 1, 2011
I have this error:
Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.
my website was designed using dotnet 2003 worked under dotnet framework 1.0 the website was working fine then i had to upgrade the server to windows 2008 iis 7.0 so i configured the website to work under dotnet frame work 2.0 and the problem started to show up
i have tried many
enableViewStateMac="false" viewStateEncryptionMode="Never" enableEventValidation="false"
<machineKey validationKey="AutoGenerate,IsolateApps" validation="SHA1" decryption="Auto" decryptionKey="AutoGenerate,IsolateApps" />
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