I am trying to disable ASP.Net Validator such that its disabled on postback.
I am disabling the validator on client side using
$('.c_MyValidator').each(function() {
ValidatorEnable(document.getElementById($(this).attr('id')), false);
});
but when the page postbacks, my page is still invalid.
I am in UserControl (.ascx) so no override for Validate() for me.
How can I disable the validator such that its enabled=false when the page postbacks.
Any ideas?
There is an example for your scenario here. Basically in server side code, set the enabled property of the validator to the checked property of the checkbox (as well as call the client ValidatorEnable). Use the Page_Load event of your user control because there is no Validate method.
public partial class CheckboxAndValidator : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
validator.Enabled = cbControlValidation.Checked;
}
}
What you can't do is validate your page in the Page_Load event. This is too early and needs to be done later in the page life-cycle once the user control has done it's bit.
Related
I'm aware this question has been asked many times before but I suspect I have a unique scenario.
I'm loading a Child Control (ASCX) and setting a Property on that Control. This works perfectly fine until postback where the property is null.
Herewith the First Class which loads the ChildControl :
protected override void CreateChildControls()
{
MyUserControl control = (MyUserControl)Page.LoadControl(_ascxPath);
control.MyProperty = base.MyProperty
Controls.Add(control);
}
Then, on my Child Control I've got the following code:
public partial class MyUserControl : UserControl
{
public MyType MyProperty { get; set; }
protected void Page_Load(object sender, EventArgs e)
{
//Exception on next line because Property is null (only on postback)
var somevalue = MyProperty.SubProperty;
Ok. Let me try to explain it.
1. Once page is created, you get full page lifecycle
2. You click on some control to create user control, and you get it
3. Now you are entering value to this control, and getting postback
4. On server side postback is handled, but as you can see viewstate actions appear as soon as page is loaded.
One of main purposes of viewstate is handling control events, to see if they are changed, or save their states or something else.
5. If on the moment, when viewstate is loaded you control is still not constructed, then all it's events and values would be ignored.
Solution either make it static control and just hide it, either create it before viewstate actions started.
You need to add the control and set properties in the Page_Init event, other wise you will lose the properties value.
In Microsoft explanations about ASP.NET page life cycle, it is written that dynamically created controls must be created in PreInit.
It worked for me.
Here is my main page :
protected global::System.Web.UI.HtmlControls.HtmlGenericControl FiltersZone;
(. . .)
protected override void OnPreInit(EventArgs e)
{
base.OnPreInit(e);
FiltersZone.Controls.Add(new PlanningFiltersSurgeonWeb());
}
This dynamically created ".ascx" control contains an hidden field :
<input id="hidTxtPaint" type="hidden" name="hidTxtPaint" runat="server" />
I am now able to retrieve its value from within dynamically created ASCX control Page_Load event, after a "submit" or a "__dopostback('hidTxtPaint')" initiated from JavaScript.
On the other hand, the hidden field's value is always empty after a POST if its parent ".ascx" control is added in main page's Page_Load event.
I'm a bit puzzled by the behavior of the default ASP.NET Authentication controls, by its lifecycle to be precise.
In my MasterPage, I added a LoginView Control which displays the nice [Login] or [Logout] links. When I am logged in and click on [logout], I set up the control to perform a redirection to the homepage of the application.
Internally, when a click on "logout" happens, a postback is triggered. The following steps happen (among others of course):
The page that fired the postback is reinitialized
The page that fired the postback is reloaded
The LoggingOut event is fired
The LoggedOut event is fired
The page that fired the postback is PreRendered
The redirection happens
The target page is loaded (LoggedOut.aspx in my case)
On most of the pages, this works fine. But some pages expect some data to be initialized for their rendering to happens correctly. When this loggout postback occurs, the data isn't correctly initialized, but the page is still PreRendered which leads to some... "unexpected behavior" >_<
My question is thus twofold:
Why does this rendering step happens since the page won't be displayed at all?
Is there a way to prevent the rendering to happen?
Thanks a lot.
Tim
PS: here's a small VS2010 sample project showing you the call sequence & page lifecycle if you want to try it out for yourself http://dl.dropbox.com/u/11764136/LoginTest.7z
There is a way to prevent the actual rendering of the page.
Stop processing the current request when you redirect the page. This can be done by giving a true parameter to the Response.Redirect method:
Response.Redirect("http://somewhere", true);
You can also do this manually by calling Response.Close();
Are you using if(!isPostBack) test to control what should be rendered/re-initialized and what shouldn't?
Venemo's answer gave me an idea that seems to be working.
Instead of relying on the LoginStatus component to perform the redirection, I registered the MasterPage hosting the LoginStatus components to the LoginStatus.LoggedOut event and fire the redirection "per hand" before the PreRender step can be called.
protected void Page_Load(object sender, EventArgs e)
{
MasterLoginStatus.LoggedOut += new EventHandler(OnUserLoggedOut);
}
private void OnUserLoggedOut(object sender, EventArgs e)
{
Response.Redirect("~/LoggedOut.aspx", true);
}
I was concerned the LoginStatus component might remain dirty by doing this but sofar I haven't found any issue with it e.g. "works until proven otherwise".
Remains the question of "why the component behaves like this" but I guess it was a design decision that will remain unanswered.
Edit: this works fine until you get the same problem for the "login" action. Haven't found a way around this one yet.
I've got a serious problem with a DevExpress control (The report DocumentMap) which sometimes requests the whole report, bypassing the caching mechanism, when the end-user clicks on the logout link on the LoginStatus control. I've tried a lot of approaches to stop dead the "logout" postback so that the report won't get generated (some reports took 5 minutes to render, so the logout action sometimes took that long). I think this is similar to your problem: you don't want to do any heavy processing if the user is logging out. So I've tried a different approach: why didn't I recognize that the postback is indeed a logging out postback? All my pages inherit from a base page, so I've set this code in the base page:
public bool IsLoggingOut { get; private set; }
protected override void OnPreInit(EventArgs e)
{
base.OnPreInit(e);
var eventTarget = Request.Params.Get("__EVENTTARGET");
IsLoggingOut = eventTarget != null && eventTarget.Contains("HeadLoginView$HeadLoginStatus");
}
Now all I need to do in my page is to surround any heavy processing with a test of !IsLoggingOut... You could even do you redirect to the LoggedOut page without having to handle any events, just like this:
protected override void OnLoad(EventArgs e)
{
if (IsLoggingOut)
Response.Redirect("~/LoggedOut.aspx", true);
}
Even if you prefer to use the event handler to do that redirect, being able to know that the postback is indeed due to a logout click is a nice thing!
In my case, I was having this problem with the LoginStatus control. I can't see why it is a useful design to post back and Render the page when the user has clicked "logout". Through some tests, I found that I had to let the page go through its entire lifecycle, so Reponse.End() and Response.Transfer() did not work.
My solution was to add event handlers for the LoginStatus LoggedOut event, and then override the Render() method in the master page to do nothing if the user has logged out. I actually had the LoginStatus nested inside a user control that was then in the master page, so I had to bubble the event.
In my user control containing the LoginStatus control, I added an event handler for the LoggedOut event. In the UserStatus.aspx file:
<asp:LoginStatus runat="server" ID="loginStatusDefault" OnLoggedOut="loginStatusDefault_LoggedOut" ... />
Then in the code-behind:
public event EventHandler LoggedOut;
protected void loginStatusDefault_LoggedOut(object sender, EventArgs e)
{
if (this.LoggedOut != null)
this.LoggedOut(sender, e);
}
Now in the master page default.master, I have already included the UserStatus control:
<c:userstatus ID="ctlUserStatus" runat="server" />
and in the code-behind:
protected void Page_Init(object sender, EventArgs e)
{
ctlUserStatus.LoggedOut += ctlUserStatus_LoggedOut;
...
}
bool IsLoggedOut { get; set; }
void ctlUserStatus_LoggedOut(object sender, EventArgs e)
{
IsLoggedOut = true;
}
protected override void Render(HtmlTextWriter writer)
{
if (!IsLoggedOut)
base.Render(writer);
}
For me, the page rendering is what was bombing out when the user clicked "logout", so this took care of the problem for all pages.
What I did was have the logout link or onloggingout control just redirect to another page, "Logout.aspx" which then handles the log out code. Works great actually.
protected void LoginStatus1_LoggingOut(object sender, EventArgs e)
{
Response.Redirect("~/Logout.aspx");
}
I've a asp:TextBox and a submit button on my asp.net page. Once the button was clicked, the TextBos's value is posted back. I'm going to keep the the posted-back text value into session, so that other child controls can access to the value during their Page_Load. However, I always get NOTHING ("") in the Page_Load method, and I can read the text out in the button click handler. I know that the "button click event" happens after the Page_Load. So, I'm asking how can I "pre-fetch" the TextBox.text during Page_Load?
public partial class form_staffinfo : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e){
string s = staff_id.Text; //Reach this line first, but GET empty value. However, I want to keep it in the session during this moment.
}
protected void btn_submit_Click(object sender, EventArgs e) {
string s = staff_id.Text; //Reach this line afterward, value got.
}
}
-- EDITED --
<%# Control Language="C#" AutoEventWireup="true" CodeFile="form_staffinfo.ascx.cs" Inherits="form_staffinfo" %>
<asp:Label ID="Label1" runat="server" Text="Staff ID: "></asp:Label>
<asp:TextBox ID="staff_id" runat="server" ></asp:TextBox>
<asp:Button ID="btn_submit" runat="server" Text="Query" OnClick="btn_submit_Click" />
Since I can't get the TextBox's text in the Page_Load, so, I didn't include any code related to session for clear presentation.
Thank you!
William
None of the values of your server controls are available for consumption in the Page_Load. Those controls are assigned after the form is validated (which is after the form is loaded) and before the form's control's events fire (like button clicks, in your example). The values posted are in the Request.Form Collection. Look in the AllKeys property and you should see a key that ends in $staff_id if you use your example posted. There may be other characters in from of the key, depending upon if the control is nested in a master page or other control.
If you absolutely must have that value at page load, grab it from the Request.Form collection instead of the user control, but I would question the wisdom of capturing the value that early in the page lifecycle. You could conceivably capture the textbox's OnTextChanged Event if you needed to preserve the value in Session.
EDIT - Additional Explanation
if you were going to create a custom event for your user control, there are only a couple of steps to it.
Create a delegate. This is will be the common object for inter-control messaging.
public delegate void StaffIdChangedEvent(object sender, string staffId);
Declare an event using that delegate in the user control that is going to broadcast.
public event StaffIdChangedEvent StaffIdChanged;
In your user control, when you are ready to broadcast (say from the Staff_id textbox's OnTextChanged event), you just invoke the event [Its generally a best practice to check to see if the event is null]
this.StaffIdChangedEvent(this, "staff-id-value-here");
The final step is to wire the user control event up to an event handler (this prevents the null situation I mentioned above when trying to invoke the event). You could wire a handler into the hosting page.
this.form_staffinfo.StaffIdChangedEvent += this.some_method_on_page;
Just make sure the method on the page has the same method signature as the delegate used to declare the event.
Events also could be wired into each control that needs to know about them (look up multicast delegates), so you could do something like:
this.form_staffinfo.StaffIdChangedEvent += this.some_method_on_page;
this.form_staffinfo.StaffIdChangedEvent += this.some_control_on_the_page;
this.form_staffinfo.StaffIdChangedEvent += this.some_other_control_on_the_page;
In any event, I generally preferred to do this type of wiring in the page's OnInit method.
override protected void OnInit(EventArgs e)
{
base.OnInit(e);
InitializeComponent();
}
and just write your own InitializeComponent method to centralize any of this wiring you have to do.
There is something else that is setting the textbox value. Could you please check if you are overriding other event that occurs before Page_Load and modifying the textbox text property. Even, posting the code where you update session variable would be handy. From the code you have posted, it should work.
Do you have autoeventwireup disabled? I could be mistaken, but I think if it is disabled your Page_Load will not fire. If you want to leave it disabled, you can always override the OnLoad event...
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
// do stuff
}
I have a web user control (ascx) that exposes an "ID" property. What I want to do is set this property when the SelectedIndexChanged event fires in a gridview in the containing page. However, I can't seem to do it.... Here's my code:
protected void grdPhysicians_SelectedIndexChanged(object sender, EventArgs e)
{
physicians_certif1.mdID = grdPhysicians.SelectedDataKey.ToString();
mvData.SetActiveView(viewEdit);
panAdditional.Visible = true;
}
Physicians_certif1 is the user control. It seems the user control is loading before the SelectedIndexChanged event has a chance to set it's property.
Any ideas folks?
ASP.Net page lifecycles can be hard to understand especially with ascx user controls which also have their own lifecycle. If you are setting the mdID property in Page_Load of either the page or the ASCX control or have hardcoded a default value into it in the XHTML, it is probably being reset after SelectedIndexChanged fires.
Set a breakpoint in grdPhysicians_SelectedIndexChanged, set a watch on physicians_certif1.mdID and step through the code using the debugger.
Yes, that is exactly what is happening. You should look at (and be familiar with) the following resource:
ASP.Net Page Life Cycle
The page will load, then the control will load, then your events will begin to fire. If you have configuration needs based on event triggers, it is best either to place those configurations in the Page_LoadComplete or Page_PreRender events of the user control in question or apply "Rebinding" instructions in the Set method of your property:
public MyValue MyProperty()
{
get
{
return _myProperty;
}
set
{
RebindMyControls();
_myProperty = value;
}
}
I have a control (.ascx) that sits on a page (.aspx). Within that control there's a asp.net update panel that encompasses everything for that control. When the control does a post back it automatically raises all the events from the control plus all the events from the page it sits on. This is causing significant performance problems.
Is there any way to stop the events from being raised that reside on the page that the control is sitting on?
Thanks
Check the ScriptManager.IsInAsyncPostBack Property.
Here is the sample code:
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack)
{
// get a reference to ScriptManager and check if we are in a partial postback
if (ScriptManager.GetCurrent(this.Page).IsInAsyncPostBack)
{
// partial (asynchronous) postback occured
// insert Ajax custom logic here
}
else
{
// regular full page postback occured
// custom logic accordingly
}
}
}