All the Google finds I ran into tell me how to use FindControl to access a control on the master from the content page itself.
However, what I'm trying to do is the opposite.
From the master page, I want to reference whichever child page is in the ContentPlaceHolder.
Why you ask.
I want the master page to know which tab should be active depending on the content Page currently in the placeholder.
This lets me avoid having each page to reference the master page and allow them to change the active tab; that should be the master page's job (if there's a way it can know whom it's enclosing).
Thanks. No rants please.
If you are looking to get the instance of the executing page class, you can retrieve it from the current HTTP context:
var page = HttpContext.Current.CurrentHandler as Page;
From there, you can navigate the page's control tree, call FindControl(), and so on. Be cautious about page lifecycle, though, as master page events tend to fire before their page event counterparts.
Related
I have the following case:
Page1.aspx this page has the master page master.aspx.
I have some code in the master page :
if (!Page.IsPostBack)
{
adjustServiceBar();
}
when i click any button in the Page1.aspxit enters the !Page.IsPostBack and execute the method !!
i want this method in the !Page.IsPostBack) only
One way to do this is to set a session variable and then check that variable to ensure your code will fire only once.
Another way is to set a hidden control on your form and play with its text or value property.
According to each scenario the solution may be very complex such as custom derived masterpages and pages that extend the current events functionality to suit your needs.
I believe it is more consistent to check for IsPostBack in content page. You can move this condition to Page1.aspx and expose adjustServiceBar() method in your master page, so that content pages can call it, like Master.adjustServiceBar().
I have a user control in the Master page. In the code behind of that ascx, I want to get the title of the page. The title is being set in the head section with tag in the child pages.
Try this
var obj = this.Parent.Page;
var title= obj.Title;
Have you tried Page.Title?
However, I think the head tag needs to be ran server side to use this
I would think Page.Title would be enough. If not, you have to ride up through the object model a bit until you get to the page. Both solutions have been detailed above. The only variation may be if the ascx is set on the master page rather than the page. Worst case here is getting the title in the master page and feeding to the ascx as the page is rendered.
Now, an understanding of why this gets a bit confusing. Most people think the page sits on the master page. But, technically, the master page is set up as a control on the page. This is largely to avoid a complete rearchitecture of ASP.NET as master pages were introduced. This means the page is requested and starts to render. Then the master page linked tags are hit and that "control" is rendered, etc. In some cases, Microsoft has provided easy short cuts, in others, you have to navigate and the navigation is upside down from many people's expectation.
I'd like someone to give what we're doing a glance-over and tell me whether we're going about it an odd way.
What I have:
We have a .master (Master Page), .aspx (Content Page) and an .ascx (User Control).
The User Control should appear on all pages, so we have placed it on the Master Page
The User Control should be initialised differently based on the Content Page it appears on. So, the Content Page has the resposibility of raising an event on the User Control, passing in some arguments, which initialises the control.
Questions:
In my mind, this removes any dependency between the User Control and either the Content Page or Master Page. Am I correct?
Is calling an event on the User Control the easiest way to pass arguments in and initialise the control accordingly?
Happy to clarify any further points, Thanks.
I would say that's OK, but I would like to seek a clarification: how does the user control subscribe to the event of the content page?
Alternatively, you could also consider creating an interface for the master page:
public interface IMyMaster
{
UserControlType Control { get; }
}
After applying this interface to the master, the interface can return a direct reference to the control. The content page can then do:
if (this.Page.Master is IMyMaster) {
((IMyMaster)this.Page.Master).Control.Initialize();
}
HTH.
I have an ASP.NET page with one control (.ascx) on it. The page (.aspx) onload assigns some text to a couple labels and passes a product ID to the .ascx control. The .ascx control, onload, takes that product ID from the .aspx page and hits the database several times, does several calculations, etc - basically takes a long time to load.
So when I'm clicking a link to this .aspx page, it is taking 7-10 seconds for the page to load. I've narrowed it down to the calculations on the .ascx control being the culprit and I've optimized the code as much as I can ... but it's still taking too long.
Is there a way to load the .aspx page BEFORE the control loads? (Maybe display a "Loading..." animation? Like used in an UpdateProgress?)
You could do this with an UpdatePanel. It will take a little trickery, but try something like this:
1) Put the UserControl in an UpdatePanel.
2) Put a public property on your usercontrol like IsEnabled that it will use to conditionally do nothing or render a "please wait." Set it false from your main page.
3) Add some code in OnInit to your main page:
if (MyScriptManager.IsInAsyncPostback) {
MyUserControl.IsEnabled=true;
}
4) Add a client script along these lines:
finished=false;
Sys.WebForms.PageRequestManager.pageLoaded(function(sender,args) {
if (!finished) {
finished=true;
__doPostBack('','');
// you can include the uniqueID of your updatepanel as the first arg
// otherwise it will refresh all update panels
}
});
or with jquery..
finished=false;
$(document).ready(function() {
if (!finished) {...
}
});
What this should do is cause an async postback to be initiated immediately after the page is done loading, which will in turn cause the update panel to be refreshed. Since you set it to be enabled when it's in an async postback, it will render itself the 2nd time.
The only possible way to achieve this is by setting it up as a separate HTTP resource. At the moment .NET is integrating the control into the page so that it is waiting unti it has everything it needs to respond.
You could do this a multitude of different ways:
Web Service that gets called via javascript
Seperate page which contains the control (and is hosted within an iFrame to appear to be on the same page)
The best way to do this would be to use an iFrame (or something similar) which will instruct the browser to request the control after the main page has been sent).
Personally, I would never use an iFrame to load content on a page - that's more like a hack than anything and plus, iframe == "bad".
But they are right, you won't be able to do anything like what you're looking for.
If the user control DOES NOT have any web controls that cause a postback (or have any form controls that you need to access during a postback), then I would use AJAX to request the data on the server after the page has already loaded and use javascript to display the content on the page.
So I have a masterpage with a login that is in an update panel. I have a child page that has a literal control that should update when the login updates. What it doesn't do is reload the method I use to generate the content for that literal when it posts back. I tried to call the method on the child page from the master page once you click log in, but I get an error that the literal control cannot be found (because it exists on the child page not the master page). How would I reference that control in the masterpage to pass it to my method?
The article below shows how the control tree works with MasterPages and how to reference different controls at different levels of the control tree.
ASP.Net 2.0 - Master Pages: Tips, Tricks, and Traps
So the scenario is that you have an update panel on the child page that when triggered doesn't update/refresh your lets say, label which is in your header on your master page.
What you do is, in the code behind of your master page create a function that changes the value of the label.
Include an update panel on the master page for the label, which is triggered by the textchanged event etc.
Now, in your child page code behind or your let say, button click event, call upon the function that exists in the master page and send the needed value in the parenthesis.
C#:
((MyMaster)this.Page.Master).ShowMessage(text);
VB.NET:
DirectCast(Me.Page.Master, MyMaster).ShowMessage(text)
This should update the label with the correct value whilst triggering the update panel on the master page and thus refreshing your label as well.
I'm about to try this now for myself, wish me luck. :D