C# - Page Lifecycle Stops After Command From ListView?
Feb 9, 2011
I have a ListView in a web form (c#/.net 4.0). There is an ImageButton in the ItemTemplate.
After a postback, the ItemCommand event fires... and then everythings stops. No other page events occur. (Actually there is one other thing: Dispose() from ExtenderControlBase runs right after the event code finishes - this site has some AjaxControltoolkit controls, though there are none on this particular page).
There are a lot of things involved here so it's not really practical to post all the code, but generally, is there anything that could cause this?
I am rebinding the ListView on each postback, because I'm handling paging on the server side. When I assign the data source to the ListView, it's initially going to have no rows. So at the time the command event fires, the DataSource has no data in it, since it hasn't yet been loaded from the database and rebound. I can't think why this would cause the entire page to just stop loading, though.
The template is just this:
<ItemTemplate>
<tr>
<td class="DataListRow"><asp:ImageButton ID="edit" runat="server" ImageUrl="~/images/nav/datagrid_edit.gif" CommandName="edit" />
</td>
// a few orther cells
</tr>
</ItemTemplate>
I'm using a file manager-type WebControl that does lots of postbacks. It's placed inside a Page that is relatively complex. I would like to prevent the WebControl from causing the whole Page to go through the lifecycle.
Is there any way to isolate the WebControl from the rest of the Page? The only way I can think of is sticking the WebControl in a separate Page and creating an iframe in the original Page. Unfortunately that also means my WebControl properties/settings are no longer in the original Page. If I want two instances of the WebControl with different settings, then I have to create a Page for each setting and reference the correct one in my iframes. Not quite as "drag & drop" as I would like.
I'm working on an ASP.NET project in which the vast majority of the forms are generated dynamically at run time (form definitions are stored in a DB for customizability). Therefore, I have to dynamically create and add my controls to the Page every time OnLoad fires, regardless of IsPostBack. This has been working just fine and .NET takes care of managing ViewState for these controls.
//1. call service layer to retrieve form definition //2. create and add controls to page container }
I have a new requirement in which if a user clicks on a given button (this button is created at design time) the page should be re-rendered in a slightly different way. So in addition to the code that executes in OnLoad (i.e. RenderDynamicControls()), I have this code:
My question is, is this really the only way to accomplish what I'm after? It seems beyond hacky to effectively render the form twice simply to respond to a button click. I gather from my research that this is simply how the page-lifecycle works in ASP.NET: Namely, that OnLoad must fire on every Postback before child events are invoked. Still, it's worthwhile to check with the SO community before having to drink the kool-aid.
On a related note, once I get this feature completed, I'm planning on throwing an UpdatePanel on the page to perform the page updates via Ajax.
I'm working with dynamic fields in ASP.NET due to a very specifc and rigid end-user requirement that would take 2 hours just to explain. Suffice it to say, I can't make the requirement go away.
Anyway, I have a working solution in place; no problems with controls loading, rendering or maintaining their ViewState. This is what my OnLoad looks like:
I'm creating a page that users can upload a file to the webserver. After upload the page will then have a link to the file that has just been uploaded, along with any other files that have already been uploaded.As I am programatcially creating links to the files which have been uploaded, I have to do this in page_init or else the link button won't fire off it's event when clicked. MY web page does all this - it creates the link buttons and when I click on them, it calls the event method required i.e. a sub to download the file.
OK, the problem I've come accross is: when I click upload (to upload the file) - the page_init sub is called, displaying all the previously uploaded files as link buttons. Then my btnUpload_click sub is called, which uploads my current file. The only prob is the current file hasn't been displayed? I can only display links in the page_init, but because btnUpload is called after the page_init, the current file isn't uploaded until after page_init and therefore not dislayed?
I would like to create an attribute I can decorate specific fields or properties with. This attribute will throw an exception if the field or property it decorates is null at a given point in an ASP.Net page lifecycle. I.E. if a property, "x", is null at the prerender stage of an ASP.Net page, it will cause a "ArgumentNullException" exception to be throw with a nice message. Or a mean message. Either way, a message of my choosing.
Is this possible with standard .Net attributes, or would some kind of Spring.Net magic be required?
I have a user control embedded in a web part. It has the following snippets of code:
[code]....
Why are some controls initialised and others not? How do I get around this if I'd like to update the Text property on currentPageLabel?
Update:
I've placed breakpoints all the way through the page life cycle and found that nextButton and currentPageLabel are never initialised. The breakpoints were placed at OnLoad, CreateChildControls, goButton_Click, OnPreRender, Render and OnUnload.
I would like to wrap Session variables in a manner similar to that discussed on CodeProject.
[code]....
Here is my question: if I have to access CurrentUser multiple times in the same page, would I get a performance improvement by assigning it to a local variable instead of accessing the wrapping property? Or does the HttpSessionState make sure the object is only deserialized once per request, so that subsequent calls in the same http request don't cost any more?
I need to capture the amount of time that ASP.net takes to execute each page request in my application, but I need to exclude any network latency. I am currently capturing render times by using the StopWatch class and starting the stopwatch during the OnInit method of the page lifecycle and stopping it after the Unload method completes. It seems that the Unload method includes the time it takes send the request to the client, thus including any internet/network latency. What is the last possible point I could stop the stopwatch in the Page Life Cycle that would not include the time it takes to send the request to the client. Would it be directly before the Unload event?
Related question: Does ASP.net finish building the response before it starts sending to the client? Or does it start sending asynchronously, while the response is being formed?
I am using ASP.Net 2.0 with IIS 5 currently.
I have this code in a class that all of my pages inherit from:
I tried capturing the execution time at the end of the OnRender method, at the start of the OnUnload method and at the end of the OnUnload method. In all three cases the difference in times was at most 1 millisecond. Even when testing this from a client in Europe to a server in the USA, the times were identical.
It seems that ASP.NET MVC just runs on top of ASP.NET WebForms. System.Web.Mvc.ViewPage in ASP.NET MVC inherits from System.Web.UI.Page which includes page lifecycle methods like OnRender and friends.
I have seen a couple of comments around the web to the effect that you should resist the urge to override these methods AT ALL COSTS!. Of course, this means that I find myself resisting the urge to do just that.Is there really that much wrong with something like the following?
public class SslPage : ViewPage { protected override void OnPreInit(EventArgs e) { // Make sure we are using SSL [code].....
One could debate the purity of putting that in a "View" but it seems plenty expedient.How dangerous/blasphemous is it to override these methods? When might it make sense?
with a commandName="confirm" and its CommandArgument the memberid from objectdatasource. I have create a code behind to put certain action to the said button..
[Code]....
But it has no effect. Did I make some mistake? I'm still new in this ASP.Net things.
i am updating data using editcommand by listview.. i got data max 50 depends on customers sometimes it has a few in the database. i am using listview and sqldatasource. when i update using editcommand in listview. it doesnt update relevant rows. it update to all data in database. why.. i have provided datasoure and list view.
Within my ItemTemplate on a listview i have a link button carrying out a delete command. As it's a custom command i use the ItemCommand to do the deleting and have a stub itemdeleting.
It works fine set out like this however i only want the delete button to be available to logged in users. If i wrap the linkbutton in a loginview and then click on it the ItemCommand and ItemDeleting never get called the page just refreshes.
I would like to know if I can do the following: when I am in insert mode, can I dynamically change the select command of and then display that result in the second dropdownlist based on what was selected in the first dropdownlist.
I would like to include the minimum code to demonstrate what I am trying to do.
I have a page on which everything is loaded dynamically.
There is a Gridview (AutoGenerateColumns=true) and in the RowDataBound I check every column for a boolean datatype. If found I add a checkbox (autopostback=true) to the cell and register the CheckedChanged event. The problem is, that I only get the CheckedChanged event, if I reload the grid in Page_Load:
I have a ASP.NET wizard that I need to use jQuery to manipulate some of the CSS styles. For example if a certain criteria is met it will hide a button:
This works great on the first page, but subsequent pages (loaded as controls .ascx) don't work. The wizard doesn't load a new page each time, but simple reloads part of the content using the built in wizard feature.
If you do a search for "ie8 back button disabled" you'll see a number of blogs with people having difficulties with the Internet Explorer version 8 back button becoming disabled. This now happened to one of my ASP .Net pages. The page uses a user control, aspx page, and a master page. It uses no redirects and seems to be happening when I click the back button and then the forward button (after the forward button is clicked, it does not fire the Load event and the back button becomes disabled). Has anyone else encountered this and do you have a solution for it?
I have an ASP.NET site at work that uses a SQL Server 2k database.
Some pages on the site have buttons to export data via Crystal Reports and the user has the option to save or open. I also export to MS Excel using Response with content type.
Everything works fine until the workload increases and many documents are exported. What happens is that the site stops exporting when the buttons are pressed. It simply does nothing.
you can still use other features of the site but no exporting.
the only solution i've found so far is to restart IIS (Hosted on a Windows 2k3 server).
this only lasts about an hour or less and i have to restart again.
We have a very simple ASP.Net page for uploading a file to our webserver. The page has no controls - a client uses it to automatically send us a file each night.
On occasion, the file seems to not get to us, but the client reports that they have sent it.
We added some logging statements to the page, and discovered something quite odd. The page ceases to execute right in the middle of a log statement. No exceptions, just up and dies.
Here is the code-behind:
[code]....
I assume if there was a error in the transmission of the file that either an exception would be thrown from the reader.ReadToEnd() line. And if not an exception, I would expect the page processing to continue but that I may only receive part of the file (in which case it should log something).
The logging statement is only accessing a string variable, and it's inside a try-catch. NLog is the logging component we use, and we access that through the facade provided by the Simple Logging Facade project on Codeplex. So, we trust the logging component to be more or less bulletproof - we certainly don't see anything in our usage of it here that should be causing problems.
Why on earth could this page just up and stop processing like this?
The fact that we get a half-finished logging statement seems to point towards an error being swallowed in the logging system - but that just seems so unlikely - and we have NLog's internal logging on and it is not reporting any problems.
Asp.Net AJAX Timer control stops ticking when I right click on the page. Actually i am updating a label using timer control for every second. When I right click on the page the label is not getting updated. I mean the timer stops ticking.
i have a page in my webapp, in which a pdf is created. When the page is loaded, parameters are read from the querystring and the process of building the pdf starts. This contains two xslt transformations and one antennahouse-fo-formatter call. The result of the first xslttransformation is written into an memorystream, which is the source for the second transformation. The result from the second transformation is the source for the pdf-generation. Our live-system is an loadbalanced-system containing two servers. The page works for a while, but at once the page fails on one server with the following exception:
Some time ago I converted an old windows application to a web application. This web application works fine as a stand alone app. I was recently informed that my client had a new standard layout and they are using a master page. They sent me the master page.
The web application is quite basic in that it makes a number of calls to a web service to retreive a list of customer, retrieve list of products and allows customer to create an order containing products.
I did the following to get make use of master page:
Copied it to my solution Update the page directive to include the MasterPageFile attribute and set it to point to master pageAdded the relevant content areas to my page Copied my code (control declarations etc) into the relevant content areas.The application compiles correctly and renders as expected. However, it does not behave as expected.
For example, I display a list of customers in a GridView. The user can select a customer by clicking the select button that is present for each row in GridView. I do this once and select a customer the page is posted back and relevant row is selected. I select a different customer and the page it posted back but this time the selected row does not change. It is still shown as the first row i selected.
This functionality works as expected if i remove the master page attribute and content areas.
