I have inherited a solution created in ASP.net with VB.net and am having a real problem with the error message "Content controls have to be top-level controls in a content page or a nested master page that references a master page."
The design is somewhat complex as follows:
The app uses a single Masterpage. The child page accessed has a custom user control on it. The user control contains, amongst other controls, an iframe. The source of the iframe is set programatically to another page, (aspx) which does not inherit from the Masterpage as we don't want the headers, footers etc. to appear in the iframe.
This aspx page has another custom user control on it that displays a small number of controls, buttons, text fields, file upload etc.)
This all works well in my IDE (Visual Studio 2005) and the file upload control is displayed properly. As soon as it's deployed to a server, (test or live) I get the error message at the beginning of this post.
The pages and code are too complex to post here but if I haven't given enough detail I will try to explain as necessary. I hope someone can help as this has been driving me insane. I've searched extensively with no success.
Many thanks.
Related
I'm working on a .NET WebForm app which has a master page. The .NET can not recognize many elements in the aspx file. For example it say Label is not a valid asp element and then says most likely reason is a malformed web.config file.
I double check my web.config and all looks good. The other webpages do not have same issue. The interesting thing is I do not have this issue inside the MasterPage.
I also tried recreate the page from scratch but still having same issue.
I'm using VS2019. Framework 4.6
You have to provide some sample code and markup. Also, if you have a master page, then that is a huge deal also. As a general rule, asp.net controls you drop on the page are able to be used from code behind. However, the code for the standard page(s) that we use as a "child" of a master pages means that code behind for the master page can easy use controls in master page. And code behind for the page being displayed in that master page ALSO can freely use its own controls. But controls between the master page and the working child page is VERY different matter.
And of course controls dropped into a repeater, or say listview (or even gridview) means that the one label or text box control is automatic repeated over and over. As such, you have to pull/get/use the one row out of that data bound repeating control, and then from that one repeating row grab the control in question.
So, saying I can't start my car, or I can't use or get a control?
We need more information as to the context of what control, where it is (in the master or child), and is the control perhaps nested inside of a data bound repeater, listview, gridview etc.
so, edit your question - add some details as to the markup, where it is (master or the child page), and we can help.
So, as a general rule, code behind in master page is free to use controls in the master page.
And in the web page you created, once again code behind is free to use controls in that page.
It can be more difficult to say have code in master page, and have it reference controls in the child page that is being displayed. But, then again, it is VERY rare that code in master page would need to reference or play with controls in the child page, since a master page will (usually) just be your main navigation bar - and it will be the same for many if not all pages you display - hence you master page really can't know what controls will exist in the current child page being displayed.
I'm having the following problem - I have a master page with an ASP menu control on it which is inherited by every content page of the web site.
The thing is that in (almost) every content page I have a form with runat = "server" and I get a compile error that I can't have 2 form tags with runat = "server" in one page (since I must put the menu control in another form tag).
How should I go about it? I'm doing this as a course project for a university course in C#/ASP.NET and it is said in the asignment that we must use master pages and we must use the asp navigation controls for the site navigation, so I can't use clear html for the menu or drop the master pages...
The first and easiest option is to remove the forms from the actual pages and use a single form for everything. ASP.NET Web Forms is designed to work that way. Since it is a university project this will be fine.
The better way is to use client side (no runat="server" form). You can handle the posts manually in a sort of "PHP fashion" by using the Request.Form object and read values off of it. This will not work if you are required to use the ASP.NET menu controls. So basically you cannot use this approach based on requirements.
P.S. Why is the post tagged with ASP.NET MVC tag? You should not have this problem if you are using ASP.NET MVC. There are other problems though.
I come from ASP.NET and I am learning Flex now. I don't know if I can do what I want in flex, so imagine this in ASP: I have an aspx page that loads a Login.ascx control, the control checks if login is correct, and if so the aspx page loads the XXX.ascx control (so there is only one control visible).
I want to do more or less the same in Flex: I have the main application with the code that connects to the database, check the login, and if its correct it loads a new module. I have made everything until the module load, I mean, I have the main application (Login.mxml) associated to a Login.as, and a Module.mxml associated to a Module.as. When the user press the login button (in Login.mxml), a method is fired and checks the login. If it is correct, it shows the new module.
My problem is that it is shown in the same page that the login page, instead of "changing" the page. I have used two ways to do that: ModuleLoader and PopUpManager, and both load the new module in the same page.
QUESTION: How can I load, inside an application, a Flex module in a different page?
If you want to build Applications, I strongly suggest you get out of the page mindset. Excel doesn't have the concept of pages in it's UI as one example. You wouldn't have links tot he formula editor or whatnot.
But, that said you should probably investigate the BrowserManager and how to Deep Link into a flex Application. Then you can change the URL in the browser's address bar when your application view change.
If your adamant about applying the page paradigm to application building
You could also use the navigatetoURL to redirect to a different page which would load a new flex applications.
I'm using Master Page in my ASP.net application, in the master page I put a ContentPlaceHolder in Update Panel to support AJAX in child pages, the question is how to stop Refreshing "master page controls" while navigating between pages?
For navigation between pages I tried to use Response.Redirect, windows.location java script with no success, shall I use the Frames or IFrames instead of Master Pages to stop Refreshing?
any suggestion to solve this issue will be highly appreciated, Thanks in advance...
If you don't want the page to refresh when switching between "pages", you will not have any good solution using master page. As others have said in different words, the master page is just a common "template" that is used by different pages. The navigation between is just like calling different pages, and of course will reload the entire page, including the master page content.
A sollution I have used with Ajax is
to have each "page" as a user
controls, and put them all in an
UpdatePanel with visible="false".
Then for navigation between "pages", switch
visibility for the user controls
to show the right "page" control.
The alternative is to use iframe.
Neither of these solutions use MasterPage.
The MasterPage concept was designed to simplify a common look before Ajax was introduced in ASP.NET. After Ajax became popular, the demand for not refreshing the entire page has been more common.
A masterpage is nothing more than extending your "normal" page with (most of the time) the default layout of your application. The master page and the contentplaceholders are rendered as a full html page. When you navigate between pages it is the normal behavior that your whole page refreshes. This is how the web works.
Working with an iframe could solve your problem. However that has some other side effects:
The whole masterpage isn't useful anymore. The content around your iframe is the "masterpage".
With a masterpage you actually browse to another url, you also see in the url bar of your browser. When you work with an iframe you navigate within the iframe to another page. The url in your browser will stay the same. When the user of your application hits the refresh button it always starts again at the default page you assigned to your iframe in the html. Of course there are some workarounds
Anyway. It really depends on your application. There are multiple solutions to work around the refresh behavior.
Having a structure like the one you've explained:
Master
Child page 1
Child page 2
...
Then you cannot prevent the page from refreshing when you switch from page 1 to page 2 etc. for you have a single "page" entity (master content + selected page content) when it's rendered to the browser.
If you want to switch betweent different app views inside the very same page (so to prevent a complete page refresh) you could use a single page (the Master becomes quite useless) with an updatePanel in which you load the different views.
You can also use iFrames, but if you have to handle any type of communication between different parts of the page (some of which are inside iFrames) I would personally advice not to use them.
I have a web site in asp.net that uses a master page. In this master page I have a multiview control with one view that has all the content for the content pages and one view that has some local content to the master page where I show error messages from all content pages.
In this error view I have a asp.net Label control that displays the error messages. Usually the label works fine, but in some few cases the label is null, which renders a NullReferenceException. Now I have handled this case by checking if the label is null before using it, but still my question is:
Why is this label null? What are the circumstances that can generate this?
EDIT: In the master page I have a method called SetErrorText that takes a string and sets the label. I'm calling this method from the content pages' Page_Load method, and this generally works fine. In all but two cases (that I've discovered so far) the label is initialised, and nothing separates these two cases from all the ones that work.
Also, all other controls in the master page are initialised, such as the View-control that houses the label.
When the Page_Load of a content page rolls around, the master page should be populated.
It seems that the problem was one of sloppiness. Someone had forgotten to delete the auto-generated Content-controls that Visual Studio throws in on all content pages where the master page has a ContentPlaceHolder-control.
If a content page has a Content-control, all controls that are placed in the ContentPlaceHolder-control on the master page will be null, it seems.
What method on the master page are you accessing the label from? Depending on the stage of the page lifecycle, the label control may not have been loaded yet
Could you be accessing it before it is created? Check the page lifecycle: http://msdn.microsoft.com/en-us/library/ms178472.aspx
I had a very similar error. In my case it was caused by .NET compiler wierdness related to the control designer file. Even if the designer file has the controls defined correctly, delete it, re-generate it and rebuild (make sure to rebuild, don't just 'build'). See the top answer here for how to do regenerate the designer file:
How do you force Visual Studio to regenerate the .designer files for aspx/ascx files?