State Management :: Persisting A Class Object?
Nov 5, 2010
I wish to persist a class object across postbacks by using a single session variable/object/whatever.
The class has about a dozen single variable properties; and about a dozen table properties; and several methods. The main table tracks rows of sporting event results. The web site will collect one row at a time for each postback. The data in the object's constructor is based on a dataset, but the data in the class will grow each time I do a postback so I don't want to loose the information in the class. The data isn't very big - it will fill a single computer screen.
Being new to programming I am thinking that I can store the dataset in the session but that would slow down the response time because I the methods would have to be called to refine the data - or maybe I can just store the entire class object in a session.
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Similar Messages:
Jun 30, 2010
my solution currently has a website project and a class library project. I am attempting to access a session object from my class library but it is always returning null. In a settings class in my class library I store these values like so:
private static SessionProperty<WebUser> _currentUser = new SessionProperty<WebUser>("CurrentUser", delegate { return new WebUser(); });
public static WebUser CurrentUser
{
get { return _currentUser.Value; }
set { _currentUser.Value = value; }
}
I can access this just fine from any aspx page codebehind like so:
Settings.CurrentUser.User.ProviderUserKey.ToString();
However, if I attempt to do the same thing from a class in my classlibrary project it always returns null.
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Mar 28, 2010
I'm having a problem with a class library I'm building. I have a class called Users and inside this class I have a property called UserInfo that is an object. Both of the classes Users and UserInfo are built using MyGenerations dOOdads. When I create an object instance of the Users class I am able to access the UserInfo property without a problem in my Windows App, however when I using the same library in a website the UserInfo property continues to return a no reference error. Like I said when running it in a WinApp I have no problems at all, I can access the UserInfo property and likewise all of UserInfo's properties. I am also having problems trying to debug the library using the website. And again I have no problems when using the WinApp. The way I've set it up is I have the Class library project open, and then I add the WinApp project and then the website project. When I set the WinApp as the startup project and run it I have no problems, I can set breakpoints and step through the code no problem. But when I set the Website as the startup project and try to debug I get a massage saying the breakpoint won't be hit. I then do what it tells me and right click on the breakpoint and set the location to allow the source to be different. This lets me hit the breakpoint, but every time I hit F10 to step I get "There is no source code available for the current location." For every step I take. This is making it really hard for me to figure out what going on with the code in the website. Sorry for the lengthy explanation. Here's the Users class, again it works great in the WinApp, just not the website.
[Code]....
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Oct 5, 2010
i have created a user control UserControl.ascx, in Code behind file of UserControl.ascx i have created an object of a class MyClass.cs,
Like
if(!Page.IsPostback) {
objMyClass= new MyClass();
}
but when i click on button of UserControl.ascx page and try to access objMyClass object then it set as null, so how to persist MyClass object when page PostBack, i wanted to keep object persist till the user access the page, when user goes out of this page then object should distroy?
[code].....
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Sep 1, 2010
I am trying to incorporate AJAX in my web project for the first time and it isn't working. I don't know how to instantiate a class once and use AJAX to update the dataset numerous times before updating the database changes using a postback.
My project is to learn AJAX with a class object. Clicking the button is supposed to increment a count by one using a class to store the count. Here is my class:
[Code]....
Here is my HTML code:
[Code]....
And here are my button click event code snippets:
[Code]....
My problem is that as I step through the code (after clicking on the second button) it instantiates a new class object each time which returns a value of 2 every time. I have tried to fix the problem by putting my counter class instantiation in the pageload event using "If Not IsPostBack Then ..." but my probem there is that the button click event block of code would not recognize the cCount class - it put the blue lines under the cCount
My goal is to have the class object available to multiple events in the code behind: especially using AJAX to build records in one of my DataSet tables Does anyone know how to handle this?
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Jan 2, 2011
I am using this code to pass variables from ASP.NET application to HTML Application:
[Code]....
The above code is run from page_laod event, and I am making some development changes on the Development Machine (say
http://eutdev02/ehrmd).
After the ASPX page is loaded, and I debug the javascript in the HTML (F12 under IE8), and can see the Cookie is found in the browser.
But, when I open the target HTML/Javascript web page (which will read the cookie prmStaffID), but the HTML Page is on the production machine (separate server say
http://prod01/Attendance.html), the Cookie is not found !!!
It seems to me that Cookies will persist only on one IIS Server, and will not be global.
Question:How I can persist the Cookie on the Client Machine regardless of the the Server Machine ?
For testing purposes, I want to send the cookie to the client from teh Development Server, but the target application is under HTML/Javascript, and I want to be able to read the same Cookie using Javascript.
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Oct 12, 2010
how can DropDownList attributes be persisted accross page Postbacks?
Example:
DropdownList1.AutoPostBack = True
DropdownList1.items(0).Attributes.Add("Attribute1","somevalue")
On Postback the attribute is no longer available (ie. attributes.count=0).
I tried persisting using the code below, but was unsuccessful:
Before PostBack: ViewState.Add("DDL","DropdownList1")
On PostBack: DropdownList1 = ViewState("DDL")
This generated the error: DropDownlist is not marked as serializable.
I than tried:
Before PostBack: Session.Add("DDL","DropdownList1")
On PostBack: DropdownList1 = Session("DDL")
This did not err but attributes were still not available.
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Jan 20, 2011
I read this article first to try to solve this issue, but I am already loading the controls in the Init phase of the page, yet viewstate is not persisting. Any ideas as to why? (Of note is that this is for a custom module in DNN and I do have some AJAX update panels on the page, though this section is not within an update panel, for what it's worth.)
As an overview of what I've got:
1. LoadControl.ascx - based on reading query string parameters, determines whether to load the master or the detail .ascx.
2. Master.ascx
3. Detail.ascx
In my master control I dynamically load either a master or detail sub-control in the page_Init. The detail page has a treeview control and then uses a multi-view control to display the panel associated with the depth of the node selected on the tree. On the panel being displayed I have a cascading ddl within a detailsview control which initiates a postback to select the child ddl based on the parent ddl selection. However, when the page refreshes after the postback, both ddls have resorted to their default selection.
What is interesting however, and I just realized this as I am typing, is that the Treeview is populated when the page comes back from the postback, so that is only possible if viewstate is being persisted right? (See the page_load code and you'll see that Call PopulateRootLevel(intTreeUserID) which populates the treeview, is not called on postbacks....hmmm.
Any ideas as to why the treeview maintains viewstate but not my ddls???? But though the tree is populated, I do have to explicitly select the node again and set the panel that the detailsview control is on to visible again too....
Here is the dynamically loaded control code:
[Code]....
And in the Detail.ascx page load I've got:
[Code]....
[Code]....
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Aug 5, 2010
I have been spending a better part of a week trying to track down why I am not able to clear all session variables in a web app (vs 2010, vb.net). What I have tracked it down to is that when I remove or abandon sessions that my html pages or codebehind access, it works, but for some reason in any of my class files where I use "Public Shared strConnection as String = HttpContext.Current.Session("strConnection").ToString" to access a session variable, it finds the old one and not the current one. I have to wait for it to time out, go in again, and it will find the new one.
I do not use Linq, and there is only one place in the whole web app that I place the connection string in a variable whcih is when a person logs in. It points them to the correct database. The sqlconnection is set for all of my listviews in Page_Init to make sure that they aren't using any session variable that they create on their own. Interestingly enough that if I use debug to go in each time, exit debug, enter debug again trying to access a different database, it works correct each time. I assume that debug is correctly killing the session variable for the classes for me.
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May 29, 2010
I am doing a POC of making my website run faster. Currently it stores huge object data in Session while passing information from one page to another. What I was thinking is to use shared methods and properties instead of session. It works, but wanted tocheck if this is an optimum way to do it. Below is the code that does not use session but still pass object data from one page to another:
[code]...
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Aug 19, 2010
We have an applicaiton that was converted to the new framework using the wizard in Visual Studio 2008. When we install the applicaiton in production and change the iis settings to use the 2.0 framework we start to see these errors in the event viewer on the web servers. We are using SQL Server Session State and have 3 web servers in a load balancer. Object reference not set to an instance of an object.</Message><StackTrace> at System.Web.SessionState.SessionStateModule.PollLockedSessionCallback...
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Jul 16, 2010
I have a problem.This particular code when used on local machine is working fine, but when it is used on serverit gives an error like " Object reference not set to an instance of an object.Exception Details: System.NullReferenceException: Object reference not set to an instance of an object._isRefresh = _refreshState == (bool) Session["__ISREFRESH"]; "
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Nov 3, 2010
global.asax:-I have defined a struct (my_struct)-I add a List of structs (List<my_struct>) to Application["MyList"] In default.aspx:-I have defined the exact struct (my_struct) and want to cast the Application["MyList"] object to the List of structs.
example: x = (List<my_struct>)Application["MyList"];
I receive this error "Unable to cast object of type 'System.Collections.Generic.List`1ASP.global_asax+my_struct]' to type 'System.Collections.Generic.List`1[_Default+my_struct]'
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Nov 9, 2010
[Code]....
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Sep 9, 2010
I have two class
e.g
List Class
Value Class
And List Class is inherits from Value Class
e.g
Public Class List
Inherits List(of Value)
Question:
I have Master Page and in master page i have user control, where i want to keep adding value in mention list class and i want to use this list class values in other pages.
How can i adding value in list class without intializing with new??
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Apr 10, 2010
I'm using session to store C# object but my session is expiring regularly.
I've given 540 minutes for session timeout. ( <sessionState mode="InProc" timeout="540"/>)
Now I want to use cookie instead of session to remove this timeout problem.
code below:
[code].....
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Feb 18, 2011
I have code :
[Code]....
Is it right?
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Apr 1, 2010
I had an xml-serialization which worked fine, but as I have just knew it doesn't work in Opera browser. I think, it's security rules don't allow to write to cookies xml-content.What can I do? Can I use binary serialization or something else?
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Oct 26, 2010
Anyway, I currently have a ajax based progressbar, which works like this: my long-task stores progress in session. Async callback retrieves progress from session, progressbar is updated. Everybody is happy... not! This only works when the "main loop" of the time-consuming task runs in either codebehind or a class with httpcontext. But all my businnes objects cannot do such thing. So, the next natural spet would be to say "move it to a static class" ProgressHelper or something, but since static classes are shared across all appDomain, I would bump into concurrence problems. So, can i have say a "static list progress" say progress["session1_progress"], progress["session2_progress"], progress["sessionN_progress"]? I cannot really see a way to update progress from inside a task in a business object, which i might want to use also in other plattforms like a desktop app?
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Sep 24, 2010
I am working with asp.net mvc and i am trying to get acces to a object that is in the cache.In the Application_Start() of Global.asax.cs i create and store an object in the cache like this:
Translator translator = new Translator();
HttpContext.Current.Cache.Insert("Translator", translator, null, System.Web.Caching.Cache.NoAbsoluteExpiration, System.Web.Caching.Cache.NoSlidingExpiration);
Translator holds a dictionary with translations.Now i want acces to this object from the cache to use functions and get values from the dictionary.I know i can acces it like this HttpContext.Current.Cache.Get("Translator") or Cache.Get("Translator") in the views But how can i use the functions of the object ? The meaning of the cache is to have a object that is accesable througout the webapp right ?
Do i have to make an object and asses the value of the Cache.Get("Translator") to it, so i can use the functions or is there another solution?
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Feb 11, 2011
On my local machine I've got a website running which uses the login control to authenticate a user and write a formsauthentication ticket to the client (which is also on the same local machine). At the login process it stores a a small serializable userobject in a session object named Session["appuser"]. Now when I open FF and login to the website all is fine so far... But here's the thing I cannot for the life of me figure out...
When I open IE8 and login to the same website, the session object which was created in FF is completely overwritten with the one created in IE. I thought that every session is unique, but now I'm really starting to feel my knowledge of sessions is almost next to nothing... Is there anyone out there that could tell me why I'm seeing this.
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Sep 7, 2010
how I can know if a session object was never instantiated?
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Apr 14, 2010
I have a Session Varaible in which I am assinged a List of "MLoad" objects (Ex:- 10 MLoad objects) from the initial search. After that basing some icon click i am trying to get the new filtered results (Ex:- say 1 MLoad object) and assigning them to the public property "ListSearchResults" (See code below). When i do this the original results in the Session are changed(10 MLoad objects are getting replaced with 1 MLoad object ==> which just been filtered). What i have to do so that the "ListSearchResults" in Session is not changed. It is now byref, how to make it byval?
in acreate an object See below code and after retreving t
[Code]....
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Aug 21, 2010
I want to create object in 1.aspx, and then send it to 2.aspx. This methods are bad, because:
1)Send object with url, like this:
http://www.example.com/?param1=123
This is not confidential.
2)[Code]....
This is bad too, because in 2.aspx this fields send to textboxes, and if user go to 2.aspx without 1.aspx,
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Jul 14, 2010
i have an asp.net web application.
[code]....
When i click button 1, a new list is created. But when i click button 2, it gives me error, saying that its a null list.
The changes i did in Button1_Click() are somehow rolled back. I want to keep the changes.
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