State Management :: Viewstate And Dropdownlist / Initial Selection Is Lost Each Time The Page Refreshes
Jan 13, 2011
I have a simple search page with a drop down list that I would like the value to persist on refresh..basically the user will select their location from the dropdownlist and this will be used to populate a gridview. After this the page is set to refresh at a set interval and use the same location data initially selected by the user. However the initial selection is lost each time the page refreshes.
p.s system is to old for ajax!
<meta http-equiv="Refresh" content="300" />
Dim connectionString As String = ConfigurationManager.ConnectionStrings("****").ConnectionString
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
If Not IsPostBack Then
Dim conn As SqlConnection
conn = New SqlConnection(connectionString)
Dim Locationcommandtext As String
Locationcommandtext = "SELECT * FROM [Location] ORDER BY [Location]"
Dim loccomm As SqlCommand
loccomm = New SqlCommand(Locationcommandtext, conn)
Dim reader As SqlDataReader
reader = loccomm.ExecuteReader()
Locations.DataSource = reader
Locations.DataValueField = "LocationID"
Locations.DataTextField = "Location"
Catch ex As SqlException
" & ex.ToString())
'"Viewstate should kick in here"
I have been getting this error a lot lately with some of my users, and I had a couple of concerns with view state and I have read so many articles but I am still lost..
1. I use masterpage on all the pages and I need viewstate for some of the pages but..
There is a page where a user will fill out the information and then submit this data to a cgi server, and it is where I get most of the Client Disconnected errors, what would happen if I disable viewstate when they click on that button?
Now when a user browses from one page to another, does the view state from the previous page get deleted? If not how would I delete it?
Does the master page have its own viewstate? Would I be able to make sure none of items on my master page are using the viewstate?
The sites I mantain are using way too much ViewState and I'd like to reduce that so the size of the page is reduced. I've done a lot to remedy this but I have an issue relating to DropDown lists that use AutoPostbacks.I have a dropdown list with a lot of list items and a good part of the ViewState usage is to hold the list item data. If I disable ViewState and set the AutoPostBack property to true, the page will post back and in the page load I am trying to repopulate the dropdown list with cached data. However, it seems that the SelectedIndexChanged event doesn't fire when EnableViewState="false".Is it possible to make this work without enabling ViewState for the drodown list?
SelectedIndexChanged event doesn't fire for the first item of the DropDownList. For any other item SelectedIndexChanged fires, but not for the first one.Could someone, please, explain what kind of magic is it?(I use Visual Studio 2008)
I haveMaster Page -> ASPX page -> User ControlUser control page is contains all dynamic bind controls (e.g Repeater) depended on ASPX Page (Only one parameter say ItemNo)The problem is, if I bound user control on page load event with passing respective parameters then it's create to much view state (I checked source file and it's almost 1.5 MB)In other way if I put one textbox, and a command button and I pass required parameter on button click and load the control then page size is ok (I checked and it's < 500KB)
Now here is the weird thing. First i am running it locally on the built in vs2008 web server.I load my control in fine, do a postback from a linkbutton, locally on my machine it all works fine, no issue.However when it goes onto my host, it falls over with the message:
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.Now i also load controls dynamically and use postbacks and things in the admin area of the site...and that works fine, however my front end just keeps failing? See the code behing below:
I have a page that loads a usercontrol dynamically. Depended on the user's actions, this control may be unloaded in Page_PreRender and a different control may be loaded instead. I am attempting to use the solution outlined by Mark DotNet Evans in this post: http://forums.asp.net/p/1491790/3814320.aspx
This all works great, except if the user clicks the refresh button in the browser just after the change of usercontrol. Then, I get an 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 assume the error is caused by the browser re-posting the request with the old viewstate that matched the control tree when the page was loaded, but no longer does. How can I prevent getting an error when the user reloads the page?
I'm not sure if this is an error or is the right work mode for sql sessions.
I'm working now with Windows 2008 R2 Web Ed. and SQL Server 2008 Web Ed.
When I close my browse and open again a new browser window I need to login again in asp.net application and a new session is created in the sessions table in sql server.
It's this normal? I remember that with Windows 2003 and SQL 2005 this doesn't happend. When I closed my browser and open inmediately a new browser window my session was retained and I could continue working without relogin.
I am working on an asp.net website using C#. The site deals with orders and therefore order lines. I would like to store the order in memory whilst it is being populated (with order lines) and once it gets submitted write it to a database.
The above logic has been implemented, but sometimes when accessing session state or storing a variable in it information gets lost. Take note that the web server is running a dual-core processor. I am also using the in proc session state server.
I tried changing over to using the out proc session state server (asp.net state service), but it requires serialization. Since the order and orderlines are actually linq to sql classes, the entitysets and entityref's fail to serialize.
Does anyone know the reason why session state loses information occasionally and possibly how to eliminate the problem?
I have a problem with a couple of web sites where my session state gets lost prematurely.
I use the Inproc session provider and Asp.net 2.0. Which of these are true:
The antivirus software disturbs the session. IIS recycles the app pool every 2 hours and it does not retain the sessions during a recycle. Index server disturbs the session. Anything else that can have disturbed the session?
I want to know that when we create custom controls, then is there State Management through ViewState done automatically or we have to handle it explicitely ?Since i have created Custom Controls that is behaving as if it is not maintaining its state on PostBack.
By default when the Session ends then the End-User should be directs to the login page and logs in again. Is there any way to open the login page in a new page rather than opening it in the same page(upon Session time out)?
I'm using sessions to track user name. I assign Session["userName"] in my login procedure. The sessionn gets timeout in about 15 minutes. What I need to do is, if the session timeouts I need to redirect the page to the Default.aspx page.
How can I do this? Any code example would be great.
I make a user control with DataList to expose pagining . I choose to use ViewState to save the state of pagining (TotalItems , CurentPage etc) , but it seems the view state of the parent page is not "synchronized" with the one from user control . It's basically the same situation like the example :
I have a dummy user control :
"<%@ Control Language="C#" AutoEventWireup="true" CodeFile="WebUserControl.ascx.cs" Inherits="WebUserControl" %>"
In my webapp page i load a custom user control, this uc loads data from an xml file in a JSGrid. All this works fine and uses callbacks. The uc is the callbackhandler and thus implements the icallbackhandler interface. Now, i gave this uc some properties, like the path to the xml file. After each callback the uc loses the values of its properties. Currently i'm including the path in each callback itself so i can load the file each time i need it, but this isn't the good way i think.
I tried solving this with viewstate but it doesn't work, a callback also seems to erase the values of the viewstate.
Is there a way to keep these values stored in the uc instance? Maybe a way to disable the erasing for each callback?
Also each callback contains "Changes", this has al the changes that were made to the grid. So when all the changes were made in the grid, i want to get these changes in my page that contains the uc in order to decide ther what to do with this data.
I need some help in the technical approach with the following scenario:-
1) A dropdownlist with some options. It has a postback action on the selectedIndexChange server side event handler. For example, lets say it contains language options such as english, french etc.
2) Repeater with a label and the textbox control. For example label is Emp Name and textbox is containing the Emp Designation. We have to save emp designation in the various languages.
3) Every time i pick something from the dropdown, i have to flip the textbox control and fill the form. Now i want to save the given data of the texbox in the viewstate. So that every time, the user changes the dropdown selection, he can see the repeater data corresponding to the dropdown selection.
4) I guess some kind of relationship between the dropdown option and the repeater data is needed. But how can we make this thing work.
Now which is the best technique to save the data on the server side? I have to keep it in the viewstate.
I have 2 front end servers and 2 back end servers. There is a registration form in my web application. The registration form uses a Microsoft Wizard control. Lets say the Wizard control has 4 steps. After the fourth step, users click "Finish" and I display the "Thank you Message". The way the request is routed between the 2 servers is round robin. So lets say till the fourth step, the response comes from server A. After the user clicks "Finish", lets say the response now comes from server B. After they click "Finish", I am trying to access some information in the Wizard control (like Name, address and so on). Because the servers are now switched, the data is lost (at least thats what I think is happening). So all entries in the wizard control are now blank and when I try to read those values, they are null.