Page Lifecycle And Not Being Able To Display Controls Outside Of Page_init When Trying To Create Them Programatically?
Nov 28, 2010
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?
When we double click to page It creates an empty Page_Load event codeblock automatically. Or you know can create other control's event subroutine events by clicking the relevant event in properties window.
but how can we create a Page_Init ? is there an automatic way ? or should we just write its name and parametes manually is the only way ?
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 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 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'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 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>
In a User Control, I need to add a Div to the end of its parent's page. I've done this in a number of ASPX pages, where I put the code to generate the Div and its contents in the page's PreRender event handler, and it works fine. But when I try to do the same thing in the PreRender event handler for the User Control, I get the following error:
The control collection cannot be modified during DataBind, Init, Load, PreRender or Unload phases.How do I accomplish this in a User Control?
am using c# with asp.net for wspproject. I am using spgridview to show the folders and files. When i clicked on folder, the spgridview bind with folder content(files/folders).Now i need to navigate folders based on the folder names like navigation bar in sharepoint.How to create the navigation bar for sharepoint folders?
I am trying to create a ad-hoc reporting system and plan to create the report rdl programatically using a wizard where user selects the attributes of the report.
point me to any documentation, sample application that I can refer to on how to create the rdl file programatically?
I m trying to load a new tab which should load WebUserControl2.ascx on button_clickbut I m coming across this eror: A Zone can only be added to the Page in or before the Page_Init event.I have a webpart in WebUserControl2.ascx which should load FeaturedControl.ascx.Well, i m getting the error when i click on button at :
Private Sub LoadTab2() Dim uc2 As UserControl = CType(LoadControl("WebUserControl2.ascx"), UserControl) tp2.HeaderText = "Tab2" tc1.Tabs.Add(tp2) tp2.Controls.Add(uc2) End Sub
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'm currently building an intranet engine for a project I've got on the go at the moment, and I'd like to save myself a little time by generating header images from code where possible, however, I'd like it to match our concept image.What I'd like to achieve is below:My issue is I've not the faintest how to create that from code. I can do the absolute basics but that's about it.
I start to fall down when it comes to the gradient background and the drop shadow on the text. I can get away with positioning the text on the larger header image, so if it's not possible to generate the exact gradient I have there, then I have a work around for that, but what I really want to achieve is the text with the font and drop shadow.I'd say it's safe to assume that to use a "non-standard" font, I'd merely need to install it on the web server?
I do some dynamic stuff with UpdatePanel controls and it would be great to store stuff in a Session key and be able to grab it immediately with confidence in a Page_Init. Fantasy e.g.,
I want something like this so that even if an individual user has two or more instances of that page open I am able to respond correctly to the immediate instance in Page_Init. Is it possible to achieve what I want or some facsimile of same? I know I can speculatively make an assumption and then check it in Page_Load when I have access to ViewState, but I would like something that approaches a best practice.
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?
Hardware involved: SQL Server 2000 Microsoft Server 2003 with IIS6 [code]...
The goal, from internal department (user) perspective:A department wants to "upload" an excel spreadsheet of data (product, term, rate, etc) to SQL (this will be from the internal network). The data is then saved to a webpage location for that department to view and approve. Once "approved," this data is displayed on the live web servers (public-facing website which is two load balancing servers). Bonus:
The .NET application/SQL Server can send an email to the department reminding them to upload the latest rates (each weekday morning, then each Thursday afternoon) if rates have not yet been "approved."
From the development perspective, this is my general idea, but I may be wrong.There are three spreadsheets, each with one tab. The first spreadsheet is uploaded, and the .NET application puts it in a SQL table. I then need to display this table of data on a .aspx page for the department to approve before the .aspx page is pushed to the live web servers.
First, I need an interface for this department to upload Excel files. I need this application to save the data to SQL and display it in a .aspx page so that the department can look it over and approve it. The department needs a way to "approve" the page, and this action will push the data to the live web servers. Will this involve SQL data transformation services?
I have this so far but kind of stuck on how to do it programtically if I'm using header and content templates I have a xmldatasource..In a nutshell at what point in my code do I need to create a new accordion? does it need to be in the item_databound handler?
How to create dynamic page in asp.net c#? in this task ... user when click on create page button. he write name of page . and simple click create page.
