I thought I knew how ViewState worked, but I was wrong.I don't understand why the following ASPX page preserves the value typed into the TextBox after clicking on the Button?(ViewState is disabled for both the page and the TextBox.)
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I am new at the ViewState and i am looking to see what values are stored within it. I know how to loop through an array to check for a value but i do not know how to go about doing that for a ViewState("test") property.
Let's say i have added "bob, tom, Jim" to a ViewState called ViewState("test"). I would like to be able to see if "tom" was in the ViewState("test"). If not then add it but if it exists already then skip it.[code]....
I have had a user of my VB.net web app complain he keeps getting an intermittent error message, causing him to crash out of the system.
Stack Trace:
[FormatException: Invalid character in a Base-64 string.]
System.Convert.FromBase64String(Strings) +0
System.web. UI. LosFormatter.Deserialize(String input) +25
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It appears from the error message that the viewstate keeps becoming corrupt (see screen-dump below), but I don't understand why. He claims it happens every 2-3 minutes, but I've used the system a lot and have never experienced it.I should mention too that he is using the web-app in a very "non-standard" way. To achieve optimum speed he's actually using remote desktop, to connect to our server directly, and running it as localhost. ("Madness!"- yes, I know. I didn't make the decision.) That may not be relevant of course.
Is it possible to make the viewstate false of whole page including all controls at a time.I mean I don't want to set enableviewstate="false" for all controls..In the page directive of the aspx page I have made enableviewstate="false" but still viewstate of all the controls of the is enabled.. And what the EnableViewState="False"actually works within Page directive.
View 3 RepliesI have a VB.Net web site and on my sign up page I am storing the ViewState in Session. I am using the following code to achieve this.[code].....
This has been working fine for months, then I started seeing the occasional 'System.NullReferenceException: Object reference not set to an instance of an object.'. The exception is raised when I try to get the value of the Text Property from the SelectedItem of a DropDownList, the problem being the DropDownList does not contain items after the page has posted back.The problem is only present when using IE (7 or 8 according to my logs, but I have only tested with 8), but not when using FireFox 3.5.Reverting to using the normal ViewState persistence mechanism caused the page to work in IE again.There are no ViewState related exceptions logged, it is like the page just 'thinks' it has no stored ViewState.
I agree that the best way to shorten the ViewState is to disable it on the ASP.Net controls that don't need it. Keeping it small from the beginning is a great habit.I have also heard that it is already compressed (although can be true... there are ways of compressing it even more, has described in this Stack Overflow question).
My question here is not if it should be compressed... is: when should ViewState be compressed?If we have a ViewState of 410 characters it will weight 410 bytes in a page, while a ViewState of 13.843 characters equals 13.5 KB.
13.5KB is a considerable weight already. And if I compress a CSS file that height 10KB, I think it is also worthy compressing a ViewState of 13.5KB, even if that means a little extra "thinking" on the server.
But is 410 bytes of ViewState worth the extra processing on the server?At what point is it worth compressing?
I have a form with its method being "get" that passes the variables and their values to the query string, respectively. However, it also passes the viewstate variable in the query string. Now, I have a very long viewstate value on the given page, and if passed in the query string, the viewstate variable will cause the page to error out, due to "too long of a query string" which happens to also be too long of a url.
I cannot merely remove the viewstate variable - I need it. But I need to pass the viewstate variable along via some method other than get when the form is submitted, while the other inputs of the form (the non-hidden inputs) are appended to the query string.
I have Dim a(15) as integer i wont to save this array in Viewstate .
View 2 RepliesI'm having some problems in persisting the viewstate on postback for a Control (vb.net)
here's some code i've put in my control[code]...
I'm setting EnableViewState = "true" everywhere i can, but still no result. Do i really need to set those properties here. (ViewStateMode and EnableViewState) If not, where should i handle this and what is the difference between those properties?
How do I convert the following ASP code (vb.net) to win form (vb.net)? I get a n error on ViewState.
Protected Sub TextBox_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) _
Handles TextBox1.TextChanged, TextBox2.TextChanged
IsSaveRequired = True
End Sub
Protected Sub SaveButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles SaveButton.Click
If IsSaveRequired Then save required.
End If
End Sub
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I keep getting the following error message when I run my vb.net web app:The state information is invalid for this page and might be corrupted.After a good search, I came across this Microsoft page, which describes the problem exactly. The likely cause seems to be "scenario 2":[code]I appear to have prevented this error from happening by using EnableEventValidation="False" in the Page node of the markup as recommended here.
View 2 RepliesI need help making this code work better. Currently, what happens is when it reloads, I loose the third value which is a calculated value . I would like for my page to reload without loosing the values for each property and each instance of the user control on the page.
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I am using VS 2008, VB and using a dorpdown listbox in my asp.net webpage. I select a value from the dropdown, click the submit button, when the page comes back from the server, the value in the dropdown is blank (default). The dropdown controls viewstate is enabled.
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I have to hide the VIEWSTATE and EVENTVALIDATION hidden fields on my ASP.net page at RUN time.
I managed to remove the EVENTVALIDATION like so.............
<%@ Page enableEventValidation="false" EnableViewState="false" %>
But the VIEWSTATE is still there and I cant get rid of it and I need to. (hard to explain why)
I have a massive viewstate hidden field that is causing my application to be unworkable. I have tried:
EnableViewState="false" on every control
EnableViewState="false" in page directive
Page.EnableViewState = false in Page_Init
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I have the following code to try to use viewstate to save a variable for postback. When post back occurs the SrString value is nothing. I have set the ViewState value at the dropdownlist index chane event and set the variable equal ot ViewState("SrString") at page in the if ispostback block.
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On my webpage I am loading multiple instances of a usercontrol, sometimes the usercontrol is laoded within itself. I need to save a bunch of properties for the round trip of a post back but i am confused on how to save those properties to ViewState and set them again to the repeater items within the usercontrol. have read the MSDN on Viewstate but I am not understanding it quite well for some reason..[code]
View 2 RepliesI have been reading up and trying to understand the difference viewstate and session and as i am only storing a database id i believe i have settled on Viewstate.
Am i right in saying that a viewstate never expires until the browser is closed? One of the issues i have with Sessions is that sometimes the people completling my websites forms can take and age to do so and the session can expire.
I have a website [URL]
have a login.aspx form and we can access with user and passs
but i want i can from site2.com.vn call a function with username,pass and use viewstate to access site1.com.vn without press user and pass
I have a gridview in asp.net using vb 2005. on " Protected Overrides Sub Render"some of the data in the columns gets modified. when i do a view source.. and look at a column1's values it says 0010. in the render i am taking a value of ab0010 and turning it into the 0010 that is seen in the view source.. later on, there is a button_click event that goes through each line of the gridview and grabs some values. Here I'm doing a CType(gvr.FindControl("column1"), Label).Text the value is coming back as ab0010. so the question is.. the view source shows something different than what is in the viewstate?
View 1 RepliesI've looked up ways to reduce the ViewState:
Viewstate Optimisations
Strategies for reducing ViewState size in asp.net
However, due to the situation I'm in, I need the quickest and most effective ways to reduce the ViewState size. The legacy system I'm working on is bloated and routinely has a ViewState that's 800Kb+ on multiple postbacks.
For example, I'm pretty sure populating drop down lists with 100+ items on multiple post backs is one of the culprits, correct?
Disabling the ViewStae entirely doesn't appear feasible. It breaks all of the controls, of which there are many, rendering the pages unusable. If this is the best approach, how should I go about handling all the broken controls?
I have written methods to override the LoadPageStateFromPersistenceMedium and SavePageStateToPersistenceMedium methods. now the problem is that i am using a masterpage, so how do i maintain using my masterpage and still inherit from System.Web.UI.Page?
Bear in mind that the .vb Code behind the masterpage already inherits System.Web.UI.MasterPage. Anybody know how i can "properly" override these methods in a MasterPage?
I have a spreadsheet with this code:
'insert link
sheet1.Hyperlinks.Add(sheet1.Range("P1"), "http://http://www.vbforums.com", "")
the code of the button (ribbon)
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When I press the button, it connects to the web site. when the sheet1 is selected, it works, but when the sheet2 is selected, not works, why? the path is sheet1,What's wrong?
I'm trying to add a row grouping row to my data-bound gridview. It works fine on the first response, but at the postback i got the "Failed to load viewstate" error.There is the code for the GridView's RowDataBound event:
Private Sub AddGroupingRow(ByRef eRow As GridViewRow, ByVal Css As String, ByVal ColSpan As Integer, ByVal Txt As String)
Dim cell As New TableCell()
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I'm having some issues with an Invalid Viewstate error and I can understand why it's happening but I don't know how to fix it so I'm hoping someone can help.
I have a page which is similar to this /story/?id=123 but I'm using a different page to Server.Transfer to this page.
So I've set up /info to Server.TransferRequest("/story/?id=123") and it works fine until the page does a postback to itself.
We have a login form on this page which simply reloads the page but when it does it seems to add /?id=123 onto the end of the URL so it ends up like this /info/?id=123 thus causing an Invalid Viewstate error.
I've already tried adding EnableViewStateMac="false" - this fixes the error but it doesn't log the user in as expected so it does not give the required result.
Is there a better way to redirect to my page other than Server.TransferRequest but still keeping the nice URL? - I don't want to response.redirect if I can avoid it.
My page has a drop down whose values are dynamically populated. Based on which item is selected, a number of TextBoxes are dynamically created during runtime.The user then fills in information into the textboxes and clicks a submit button.After postback from the submit button, I need to again dynamically create the TextBoxes during Page_Init (BEFORE LoadViewState) so that after the ViewState loads, my Button_Click event can save/do whatever with the user input. PROBLEM is, I cannot recreate the textboxes based on the selection in the dropdown, because the dropdown hasn't been "selected" yet by LoadViewState.SO, how can I read from the view state, create my textboxes, then let the viewstate populate the textboxes, and then the Button_Click will use the values??The one thing I've attempted is to override the LoadViewState function so that I can read from the view state, create the boxes, and then load the viewstate again. This did NOT work, because the debugger never seemed to hit my overridden function.[code]
View 1 RepliesI am adding controls to a page programatically in the code behind. I add an asp:Label and set it's Text value. I add an asp:TextBox and set it's Text value. Both Text values are returned in the Response and displayed in the browser. All fine so far.
The user performs an action that causes a postback. I re-load the dynamically added asp:Label and asp:TextBox. When the Response is returned to the browser, only the asp:TextBox Text value is displayed. The asp:Label Text value is not. If I inspect the HTML I can see the asp:Label control (rendered as an HTML span tag) but no value.
How can I get the code to automatically re-load the Text value of an asp:Label on each postback? Why is the behaviour different for an asp:Label and an asp:TextBox? I do not want to have to manually re-set the Text value on each postback.
Here is some code similar to what I am doing (placeHolderNameplates is an asp:PlaceHolder control on the aspx page): Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
If Not Page.IsPostBack Then
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Right now I have controls that are in my update panel and change the data in my gridview they work fine, but then i thought it would be cool to have the controls in the header of my gridview. But when i add them to my header and hit the button/run the function i get the failed to load viewstate error.[code]
View 3 Repliesthis is my code:
Dim WB As WebBrowser
WB = GetPage("http://speed.travian.ir/a2b.php?z=" + VillageID.ToString + "&c=" + Type.ToString + "&" + AttackParams)
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I have created lots of applications with visual basic 2008, tested them on many other computers, worked like a charm. After I moved to 2010, all my applications compiled, ran without a problem even on different machines (worst case scenario was that some older PCs needed the 4.0 framework to be installed first). Anyway suddenly I ran into a very weird problem which I cant figure out.I have Visual C# 2008 (Express Edition) on this machine installed and everything ran/compiled flawlessly but when I tried the application on a different computer, it can't even start. It crashes as soon as you attempt to run it and displays that 'Application Stopped Working' error.
I also tried to compile it as Release, then start the exe .. still the same problem. Sorry again for asking this on a VB forum, I just started playing around with C# after VB and didn't know where to ask.Aditional Info: Visual Basic 2008 and 2010 programs work perfectly on the same machines on which Visual C# 2008 doesn't. (I would be glad if some one could at least re-direct me to somewhere else )