I am receiving the following error message after an HTTP POST on an ASP.NET form hosted inside a UserControl:
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. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request.
Here's additional info:
I'm running .NET 4.5 RC
It's an Umbraco 4.7-based website
On my local dev machine the form works perfectly
This error only occurs on the staging server which has .NET 4.5 (only), MSSQL 2012 Express, IIS 7.5, Windows 7 (I know, it's not a real server yet, one day maybe...)
The server is not part of a web farm (or garden, tho that should be irrevelant)
The user control does render controls dynamically
I have applied all the latest service packs.
I have run out of ideas now! I have even restarted it and also performed a richual over the server involving a song and a special dance to no avail.
What is important when you are adding controls dynamically is on which event you are adding them.
If you added controls on events that occur after load, they will be part of the viewstate you send to the client.
You will have to add those controls again before LoadViewState is called.
If you run into cases where the decision of which controls to add is itself stored in the ViewState or the value of a control, then remember even before the ViewState is loaded, this data is available in Request.Params
Refer the asp.net page life cycle
I just added EnableViewState="false" to my page placeholder and its gone. Hope it works for u as well.
This Error Mainly Occurs during View state Change: From One Template To other Template like in case of Item Template, Edit Item Template, in Controls like Form View, List Views, Detail View, Grid View in ASP .net (all frameworks);
While Changing from control states say Item Template ---> Edit Template
the followings were going to alter
1) Controls will change (its ID & states)
2) Its Positions will change.
While Transformation of view if any post back occurs you will get Error as
Failed to load viewstate. The control tree into which viewstate is
being loaded....
if you are using separate control for data-binding like (button,link_button_Image_button events) you will get this error reported !
To avoid this error >>> Once state changes from one template to other within method you call data source binding ( Don't call during click or any post backing events ).
OK, so the answer is literally: "Set up a new server with all the same software as the last one and try again" and it works now.
I add "name" attribute with the same value as id, then this problem is gone.
<input type="button" id="extractBomInfoBtn" name="extractBomInfoBtn" value="Extract" class="button textonly" />
I had the same issue. This issue was at client end but it didn't occur in my local system.
After hours of googling, i had written EnableViewState="false" to my table tag in aspx page which has all the dynamic controls and then i removed all the viewstate variables and instead i created some hidden textboxes in the aspx page and accepted DB values into them in code behind and used them throughout my code. It then solved my problem.
But still, i couldn't figure out what was exactly the problem.
In my case I was manipulating the .Text property of a asp:Literal on page load which was causing the issue. In all other cases this never caused me a viewstate error but in this particular case I was changing the .Text value to an html element.
The following caused the error:
<asp:Literal ID="SvgIcon" runat="server" />
SvgIcon.Text = "<svg version=\"1.1\" id=\"Layer_1\" bla bla />"
I was able to resolve the error by adding EnableViewState="false" explicitly to the control:
<asp:Literal ID="SvgIcon" runat="server" EnableViewState="false" />
Check if you have the binding method of the control directly in your page load event. This can cause this problem.
You can add new PlaceHolder per UserControls
OR
You can set enableviewstate=false on the control , if you dont need viewstate
In my case I had a grid view with (OnPageIndexChanging) event
and when I click on a page nothing will happen until I click it twice!
I was refreshing the data source before setting new page index.
This is what I was doing wrong
grd.DataSource = data;
grd.DataBind();
grd.PageIndex = e.NewPageIndex;
This is the right way
grd.PageIndex = e.NewPageIndex;
grd.DataSource = data;
grd.DataBind();
This can happen if you override SaveViewState in your control but don't override LoadViewState.
So I actually ended up discovering that the list of entities I was binding to was not in the same order as the controls in ViewState! I'm still working thru a cleaner solution, but my code is working with ViewStateEnabled = true by having the method which reconstructs my dynamic controls (called from Page_Load) do it differently if !IsPostBack.
Ultimately, I will probably need to fix my sorting algorithm for my nested dynamic controls, but suffice it to say: if you are using the same pattern as I am, of using a List to generate/bind to dynamic controls, and that order is fluid or changing, try comparing Request.Params to find the keys that are relevant to your control hierarchy, and see if they match the order of your List. That solved my issue. Kudos to #nunespascal!
In short, I am dynamically generating all but one tab in an AjaxToolkit tab control, and then populating that with a couple layers deep of placeholders and regular controls (textboxes, dropdownlists, etc), so that's why it's complicated to get the order of everything correct.
Although this is very old question, I had visited this as I got the similar issue. But my issue was generated just because I have added a javascript code in Master page in head tag. That javascript code is reading a value of Session["KeyName"] ,
Code is like below -
$(document).ready(function () {
var allowOpenInNewTab = false;
allowOpenInNewTab = '<%# Convert.ToString(Session["AllowOpenInNewTab"]).ToLower() %>' == 'true';
if (!allowOpenInNewTab && window.sessionStorage.tabId != '1') {
alert("This page is not allowed to be open in another tab, sorry we can not load the page!!");
}
});
When I remove above code then everything was running smoothly but if I keep adding this part of code, it was giving this error of
Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate...
Finally I found the solution like if I move my javascript code from head to just before the end of the body tag.
So solution that worked for me was moving javascript code (which is reading Session value from Server tags) to just before end of body tag.
I have a literal in my aspx called xxx.
Now lets go into the JS world.
I always used :
alert('audit.aspx?claim_id=<%= xxx.Text%>');
But Ive seen a code like this :
alert('audit.aspx?claim_id=<asp:Literal id="xxx" runat="server" />');
This is also working.
Can I conclude that the <asp:Literal is equal to <%= syntax ?
I know that he is a RUNAT server Item...
but again - I want to see the differences.
The asp:Literal control simply outputs the value of its Text property when the page is rendered. That's why the resulting JavaScript looks the same when viewed by the client. But the two are not the same, no.
<%= xxx.Text %> explicitly reads the value of this text property and writes it out. The Literal control will be elsewhere on the page, where its Text property will also be written out.
Placing the asp:Literal control within your JavaScript relies on the rendering of this control to place the value there, and because this is its location within your page, there's no need to have the same content rendered elsewhere.
However, neither taken in isolation seems an appropriate use of this control to my mind. If you have simple text you want written out, then expose it as a property of your Page-derived code-behind class.
The Literal class is basically a placeholder for text, but it also exposes events which you can hook into for greater control.
Have a look at the API here http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.literal.aspx
Ok, so here is the setup. I have a master page. The page is assigned to a aspx file programatically in the PreInit function. This all works as expected.
I have a function that runs through all the controls on the page an looks for ContentPlaceHolder controls with specific IDs. When a specific ID is found the control is processed (specific content is placed there based on the ID and other information). This all works as expected.
I have a situation where I would like to pass information to my processor function from the control. I would like to be able to, based on an attribute, do different things. For example I would like to be able to put something like this on the masterpage:
<asp:ContentPlaceHolder id="CMS_EXTRABLOCK1" type="text" runat="server"></asp:ContentPlaceHolder>
Note that the type="text" attribute is not a standard attribute. I would like to be able to in the c# code do something like where ctrl is the ContentPlaceHolder.
if (ctrl.Attributes["type"] == "text") {} else {}
Now none of that will work as I get a parse error with the added attribute. So is there a way around the problem while still using the ContentPlaceHolder control? If at all possible I would like to continue using the ContentPlaceHolder control type for consistency with the rest of the code. If I can't use the ContentPlaceHolder in any manner then what would be an equally ideal asp control for this type of situation?
I want to do something like this:
Panel divPanel = new Panel();
divPanel.ID = "divPanel";
this.Page.Controls.Add(divPanel);
string script = "function alertID(){alert("the id is: "+divPanel.ClientID+");}";
this.Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "scripttests", script);
But when I put this code in page_load, I don't get the full id, which is ctl00_ContentMain_divPanel, I just get divPanel.
Is there another event I should use? How do I make this work?
PreRender is fine, however it should work in Page_Load as well.
http://msdn.microsoft.com/en-us/library/system.web.ui.control.clientid(VS.71).aspx
Is your script rendering code running in page_load as well? They are together in your example above, but perhaps they were just copy/pasted together?
If this code is in a custom control, you also need to add the INamingContainer interface to the control declaration for ClientID to work as you expect:
http://msdn.microsoft.com/en-us/library/system.web.ui.inamingcontainer.aspx
Additionally, if this is a custom control, you should add to the Controls collection of the control itself, not the containing page. ie: this.Controls.Add() instead of this.Page.Controls.Add()
In your example you are adding directly to the Page controls collection. This would mean that the client id should be divPanel. Perhaps the client id you expect it to be is the incorrect one.
Is there a difference in behavior between adding a control to the ASPX page directly and loading a control programmatically and adding to a placeholder?
The control inherits from System.Web.UI.WebControls.DataBoundControl.
The reason I ask is that I have a control that works when I add it to the ASPX page like so:
...
<blah:GoogleMap ID="GoogleMap1" runat="server" Width="640px" Height="600px" ... DataSourceID="_odsMarkers" DataAddressField="Address" DataTextField="Description">
</blah:GoogleMap>
...
But not when I use the following in a codebehind page:
GoogleMap map = (GoogleMap)this.LoadControl(typeof(GoogleMap), new object[] { });
//... set properties
this.placeholder1.Controls.Add(map); //add to placeholder
Anyone have any ideas why this might be the case?
The control tree ends up the same if you define in markup or add programmatically. However there is plenty of room for the control implementor to screw up along the way.
You can go look how ASP.NET compiles the aspx:
C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files
The timing when the control is added to the page might be an issue. The usual pattern is add the control in an overload of the CreateChildControls method. If the control needs to resolve viewstate you need to make sure this is called during init, e.g. by calling EnsureChildControls.
Adding to ninja's debbugging hint. Does it make any difference if you add a label the same way. Does it show up?
Is this a user control or server control?
If it's a user control they should be loaded by their path and not their type:
GoogleMap map = (GoogleMap)this.LoadControl("~/Controls/GoogleMap.ascx");
If it's server control then you can just new up an instance:
GoogleMap map = new GoogleMap();
after you have the instance and add it to the control tree (by inserting it into the PlaceHolder) it should perform the same as when it would have been declared in the markup.
If you are setting properties outside of the LoadControl call, why are you making that new empty object array instead of just using the overload that has one parameter?
Also, if you attach a debugger to it and step through, do you notice anything weird about the control before you do your Controls.Add() call? Is there an exception being thrown? if so, which one? if not, what does the markup in the browser look like for where the placeholder is?
"Works" is kind of ambiguous, but if you mean, event handlers are never executed, you need to load it in the page onload event.
If the control requires the use of viewstate you must ensure that it is added to the page BEFORE the Page_Load event, otherwise viewstate will not be populated and most likely events and other items will not function properly.
One important difference is that if you create a control dynamically, you will not get, by default, any values from skins set. You must manually call control.ApplyStyleSheetSkin(page): http://msdn.microsoft.com/en-us/library/system.web.ui.control.applystylesheetskin.aspx