Web Forms :: When Does The Constructor On A Page In Webpage Lifecycle Get Called
Feb 17, 2010when does the constructor on a page in asp.net page lifecycle get called?
View 1 Replieswhen does the constructor on a page in asp.net page lifecycle get called?
View 1 RepliesWhen exactly is the view state accessible from the .Viewstate property of a control? From my observations, the closest event is on the Page.PreLoad event (at Page.InitComplete, Viewstate is still unavailable).
However, for controls that implement the IPostBackEventHandler interface the LoadValue() method is called and the .Viewstate collection is available (this occurs after Page.InitComplete and before Page.PreLoad).
Does anyone know of any additional events that can be used to know when Viewstate is available? Or any tricks (not excluding reflection on private/protected/internal members) that can be used to know if the Viewstate has loaded or not?
the exact difference between PreInit and Init in the ASP.NET Page LifeCycle ?
View 10 RepliesAccording to the msdn documentation, as you can see on the diagram, a server control's "Data binding events" occurs after all "control changed events". So in the case of a DetailsView control, the ItemInserted event would happen before the database operation?
View 1 RepliesDoes the OnActiveStepChanged method of an asp:Wizard control get processed after Page_Load and before Page_LoadComplete?
View 1 RepliesI'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 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:
protected void Page_Load(object sender, EventArgs e) {
LoadGrid();
}
But this is very expensive and causes that the db request will be executed twice. If I changed the code to what I want:
protected void Page_Load(object sender, EventArgs e) {
if (!this.IsPostBack)
loadGrid();
}
I get no CheckedChanged event.
Is there a possibility to get:
- Adding a Checkbox in RowDataBound
- Only "LoadGrid()" if it is no PostBack
- Getting the CheckedChanged event of the relevant row
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 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.
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
RenderDynamicControls()
}
private void RenderDynamicControls(){
//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:
protected void MyButton_Click(object sender, EventArgs e)
{
RenderDynamicControlsALittleDifferently() [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:
[code]....
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:
readonly Stopwatch _serverExecutionTime = new Stopwatch();
protected override void OnInit(EventArgs e)
{
_serverExecutionTime.Start();
base.OnInit(e);
}
protected override void OnUnload(EventArgs e)
{
_serverExecutionTime.Stop();
base.OnUnload(e);
}
UPDATE
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?
I have created one user control for changing the theme of the page where i have several buttons and on click of each button i am applying the theme of clicked buttons color and for that i have created several css files like red.css, blue.css , green.css etc.
now i want to apply this theme to the page but i am not able to do that from the user control as because i am not getting the stylesheet property in the page and thus i am not able to work further.
can anyone tell me how can i apply the theming from user control to the page its being called.?
I have an ASP.NET webform where I initialize an array with a list of controls on the page like this
FileUpload[4] = new FileUpload[4];
public myclass()
{
fileUpload[0] = FileUpload1;
fileUpload[0] = FileUpload2;
...etc
}
I then use these in the page load and they are all null. they are null in the constructor but why should they be null when used in the page load.
I want to create and render a dunamic page. Something like following:
[Code]....
But at RenderControl line, I get following Error:
RegisterForEventValidation can only be called during Render()
Is there a way to resolve it? At many forums I found set the EnableEventValidation=false in page directive. But this is a dynamic page and has no directive. Further this property is not available when I browse mypage properties.
I have the below structure. Admin_note --> AdminBasePage --> System.Web.UI.Page.But Page_Load does not call in AdminBasePage when calling page_load in Admin_note class.Do you know how to solve??
//// One file///
namespace UI.Admin
{
[code]...
I use a commercial web application that has the ability to use web triggers in order to do additional validation prior to saving its forms. The commercial web application simply makes a request out to whatever asp, php, etc. code that you've written... and in the case of asp.net I've validated forms by pulling variables off of the page.request object and then passed back a success/fail message to the commercial app using JSON.
I would like to use asp.net to display a modal popup control when called, in order to display some options. Because I would be triggering this code from a commercial web app, I'm wondering how I can display the popup control on top of the requesting page? The code I've currently written displays a blank page with my popup control on it. Is it possible for me to display ONLY the popup control when called from another website?
I just discover why some validation is working bad on some of my forms: the button click event is being called before page load.
What I need for good is (I consider this is a normal cycle of events):
The user press a buttonSome validation occurs at client side (js function returns true if success)Some validation occurs at server sideThe page loads again showing the results
But this is what I get (BAD):
The user press a buttonSome validation occurs at client side (js function returns true if success)The page loads showing no results, because server validation hasnt happened yet Some validation occurs at server sideThe page doesn´t loads again and I cant see the results, so my client cant know what happened on the server side
This is how I tried to implement this:
[code]....
Using Forms authentication, for some reason my login page is called 9 times. it causes some browsers to show "too many redirects!". Even with no javascript and nothing in the page_load event, it is called 9 times.
View 2 RepliesCan a required field validator be called from the code behind page?We have several check boxes and some of them require the user to enter a date, but not all of them.(This is not a checkbox list, but individual checkboxes).Any 1 of 6 different checkboxes selected makes a txtBox visible for users to enter a date.If they don't select one of these checkBoxes which require a date - it doesn't matter, the form will still be valid.I don't think validation groups can work here so looking towards doing through .vbHere's the existing code:
Public
Sub chkBoxI_CheckedChanged(ByVal sender
As
[code]...
I want to ask that if i have 3 content pages and 1 master page , e.g.
1 - Site.master
2 - DailyLog.aspx
3 - ProjectMaker.aspx
4 - ProjectProfile.aspx
so adding this c# coding :
protected void Page_Load(object sender, EventArgs e)
{
Session["Name"] = "Mudassar";
Configuration config = WebConfigurationManager.OpenWebConfiguration("~/Web.Config");
SessionStateSection section = (SessionStateSection)config.GetSection("system.web/sessionState");
int timeout = (int)section.Timeout.TotalMinutes * 1000 * 60;
[Code] ....
to only DailyLog.aspx , is sufficient for all pages ? because i want to show alert on every page ... Or do i have to insert the above c# code in all the content pages ?