An interview question someone asked me but I was left stumped.
If you can implement user controls inside a normal aspx page, what is the use of a master page then ?
A master page defines a layout template. You put things like styling and scripts in the master page, then call them in any page derived from that master.
It's a way of being able to split presentation out from functionality, and things you need everywhere can be put in the masterpage.
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 have two web-form pages in ASP, one for viewing a record and and another for editing it. I would like to have a link on each which popups a box to allow editing a certain property on the record. If I only placed it on the Edit page, I would use an UpdatePanel but I would have to copy and paste code if I wanted it on the View page as well. Is there a way to have the code in one area which be can be referenced and used from both pages?
Edit: I know I could make a custom control to handle it although it would include all its HTML on the page when the page first loads, not when the link is clicked.
Edit2: I wanted to avoid having the contents of the popup rendered when the page first loads but now I realize it's just a matter of not binding any data in it until the Postback occurs.
You can use a MasterPage for both the pages, and put the popup with UpdatePanel on the master page, so you can access it from both the pages.
Hope it helps.
Don't forget to upvote it if it solves you problem.
Thanks.. :)
Make the bulk of the panel a user control (ascx). Then just put a thin wrapper around it on both the pages where you need it. The bulk of the code is then in the ascx and ascx.vb and does not need to be written twice.
I have more than 100pages in my project & a single master page for all this. My masterpage has links to different pages. I want to change only the ContentPages( Child Pages) & my masterpage should not get reloaded.
For Example:
My Master page is : SiteMaster.master
Child Page1: Add.aspx
Child Page2: Sub.aspx
When I execute, Add.aspx comes inside the SiteMaster.master. Know, When I click the sub.aspx link inside the Add.aspx, only add.aspx page should be changed & sub.aspx must be loaded. I don't want to reload the master page.
If possible, please post some examples or links.
Your expected behavior is not exactly how master pages work. There may be ways to achieve a no postback solution in this scenario but the easiest one would be to use an <IFrame /> (which is usually frowned upon)
Master page is part of your pages. It's not loading separately.
Simple explanation:
ASP.NET engine takes your aspx and puts it inside the master page and then renders it as one page, then serves it to user.
If this is not what you want and you want that only content of your master page be loaded, then you should not use master pages at all! It's against nature of master pages. they act like skins for aspx pages.
Search for HTML IFrame tag and don't use master page.
P.S: IFrames are not used widely in this days.
I want to create a master page for my already developed project.Since the project contains many forms it is quite difficult to include the master page in each form...Is there any possibilities to include the master page in any other simplest way...
Please give some suggestions..
Thanks in advance...
As far as I know, there is no easy way to do this.
You'll have to manually add the masterpage to the page directive
<%# Page MasterPageFile="~/Masterpage.master" ... %>
add the relevant content sections around your pages markup:
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
</asp:Content>
and remove the <html>, <head>, <body> and <form> tags from every page.
Update
Here is an article (and source code) by Bob Powell describing a way to automatically convert html files to aspx files and add a master page. I'm sure you could adapt it to your needs.
This transition is not an easy one to make, as #geoff indicates. It is possible though if you have enough time and patience. The first step is to take all common elements (layout, menu, header, footer, whatever is common) and develop a master page structure. You'll likely need more than 1 depending on the differing layouts of forms in your application. Develop a user control for each of these common sections and make sure the master pages use these controls. Then systematically go through each page of your site and begin implementing the master pages.
As an assistance mechanism, you'll also probably want to have a page baseclass that is capable of communicating through the master page to the contained user controls. In our group we have a standard for setting a property on UserControls and MasterPages called ParentForm that is of type of our primary base page class, and this property is set during the Init of any page or control so that at any time, the developer has access (through Intellisense) to page itself. This is especially helpful since the parent of most controls is a container whose parent is a container whose parent ... you get the idea. For our controls it's just this.ParentForm.
It will be a long process, but MasterPages were really intended to be a "ground up" architectural decision rather than an "employ later" concept.
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.