I want to use page templating in ASP.Net (Visual Studio 2012 with .Net 4.0).
The base page emits the basic template inclusive of the body, html, form, and other tags. That means the rendered pages just have what goes inside the body part. The template adds the header and footer. Although I have not finalized a design, I am looking at a concept documented here. (Yes, I know that coding practice is to not give links to pages, which can go away, but I do not want to side track the question.)
The part of each page is:
<%# Page language="c#" Codebehind="AdvancedPageInheritance.aspx.cs" AutoEventWireup="true" Inherits="PageInheritanceSample.AdvancedPageInheritance" %>
Anything after that first line is part of the body.
If I drag and drop controls onto the form, VS2012 emits code such as:
<asp:CheckBox ID="CheckBox2" runat="server" OnCheckedChanged="CheckBox1_CheckedChanged" />
<asp:Button ID="Button2" runat="server" Text="Button" />
VS2012 automagically emits the warning, "Unrecognized tag prefix or device filter 'asp'."
One thought is to simply add in the body stuff programatically, but that is a page. I rather use the GUI.
How can I avoid the warning? Is there a better way to do templates? That author wrote the article 10-years ago, so things might have changed since then. The warnings are understandable, but in error, as there is a form, body, and html tags, just not directly visible.
(I just answered my question by catching a phrase in Vs2012 and researching it a bit. Master Pages are the answer. Obviously, Microsoft must have added that with either VS2008 or VS2010. I will leave this post, as others, like me, may not know the concept "Master Page" and may reserach page templates, just like I did. I hope that this post says other people time. Google should hopefully pick up on ASP.Net and Page Templates.)
Ideally you would use the MasterPage for laying out your main template.
Your Content pages would then have the appropriate <asp:Content /> controls, where you add your content. To add a content page you would add a new 'Web Form' item in Visual Studio and, by selecting the 'Select Master Page' checkbox, you can choose the master page the content page should use.
See Here for a tutorial on Master Pages
Then you would use a BasePage for site-wide code; for example anything that has logic needed on most pages. Your Content pages would inherit this BasePage
As a side-note, see this page Unrecognized tag prefix or device filter 'asp' in VS2012 with regards to your "Unrecognized tag prefix or device filter 'asp'." message
My question is how do I embed ASP.NET code in my HTML document. I'm very new to this stuff and not sure how to incorporate my ASP.NET code to be executed into my webpage. I have already crafted the code to be used in my site, however, I have no clue how to add this code so that it will be executed in my webpage.
I basically just want to update a HTML table when a form is filled out and the submit button is pressed. I also want to be able to add multiple rows to the table without overwriting the original ones. I've figured out how to update my table dynamically, but just don't know how to incorporate it in my webpage.
For example, PHP (at the tope of the page):
<?php
//PHP code....
?>
What about ASP.NET code?
Any direction/help would be greatly appreciated.
The <% %> tags can be used to include ASP code in any part of an HTML document.
<html>
<body>
<%
response.write("My first ASP script!")
%>
</body>
</html>
Source: http://www.w3schools.com/asp/default.asp
I am looking to display this in my .aspx page, without using special character XML tags, can this be achieved?
<asp:ServerTag Property1="a"
Property2="b"
Property3="c" <%-- Comment why this particular property is necessary --%>
Property4="d" />
However, I am greeted with the error message Server tags cannot contain <% ... %> constructs. If I use an HTML <!-- --> tag, I'm told the server tag is not well formed.
Is there any other syntax to make this possible?
Put server-side comment above your server-side control.
<!-- client-side comment (html) - appears in html source but not rendered on page
<%-- server-side comment - stripped out on server, never sees light of day, browser never knows about it
like this
<%-- Usage:
Property2 is xyz...
Property3 will .. abc. Ignore Property 1 when this is set. etc
--%>
<asp:ServerTag Property1="a"
Property2="b"
Property3="c"
Property4="d" />
It's just like putting source code comments above your functions.
Think "server to server". It will make the difference between your HTML source looking like
cluttered with "pass through" html comment <!--:
<!-- Property usage: abc, def, ...xyz -->
Rendered server control contents.
vs. the cleaner stripped out " <%-- source:
Rendered server control contents.
Less bandwidth with latter too. No extraneous (and confusing to user) comments in HTML source.
It's not possible, no. The server tags need to be well-formed XML and you can't have tags like that in XML. You can put a comment at the top, of course, like so:
<!-- Property2 needed because... -->
<asp:ServerTag Property1="a" Property2="b" Property3="c" />
Not necessarily like that but you may want to consider decorating the property in c# to let the user know its relevance. After that something like resharper (or maybe vs) will give you this information when you try to set it.
After trying to understand why client code is not rendered in a page (injected by user control) I found this link, it turns out you must have a form tag for it to work (Page.RegisterClientScriptBlock did declare this but ClientScriptManager.RegisterClientScriptBlock which I use does not say anything regarding this).
I am using Visual studio 2005.
Does anyone know if this has been solved?
Edit:
To clarify, I want my control to add javascript code to the head section of the page without having to use the
<form runat="server"
I have tried adding it using:
HtmlGenericControl x = new HtmlGenericControl("script");
x.InnerText = "alert('123');";
Page.Header.Controls.Add(x);
But this did not work for me.
As far as I know this functions the same in current versions, you can test it very simply though.
Update
per discussion in the comments, the only "workaround" that I could think of would be for your to manually insert the script into the "head" section of the page on your own, using a runat="server" declaration on the Head element.
Got it!
My mistake was not doing it in the OnPreRender method (I used the Render method).
Now all that is needed is - like Mitchel Sellers wrote, set the header to runat server and than add to it's controls:
HtmlGenericControl x = new HtmlGenericControl("script");
x.InnerText = GetScriptSection();
Page.Header.Controls.Add(x);
Thanks for pointing me to the right direction!
The MSDN Page for registerclientscriptblock here says:
The client-side script is emitted just
after the opening tag of the Page
object's <form runat= server> element.
The script block is emitted as the
object that renders the output is
defined, so you must include both tags
of the <script> element.
If you do not want to include a form, than you will basically need to build your own implementation of it.
Minor clarification for anyone seeing this:
The form tag must have the runat="server" attribute set, e.g.
<form id="theform" runat="server">
Just placing a regular HTML form tag in the page will not help.
OK, another road bump in my current project.
I have never had form elements in both my master and content pages, I tend to have all the forms in the content where relevant.
In the current project however, we have a page where they want both. A login form at the top right, and a questions form in the content.
Having tried to get this in, I have run in to the issue of ASP.NET moaning about the need for a single form element in a master page. TBH, I really dont get why this is a requirement on ASP.NET's part, but hey ho.
Does anyone know if/how I can get the master and content pages to contain form elements that work independantly?
If not, can you offer advice on how to proceed to get the desired look/functionality?
Thought I would review some of my outstanding questions and see if I can close some of them off.
This one was an interesting one. I outright refused to believe you can only have one form on an ASP.NET page. This to me made no sense. I have seen plenty of webpages that have more than one form on a web page, why should an ASP.NET page be any different?
So, it got me thinking.
Why does a ASP.NET page need a form element?
ASP.NET pages try to emulate the WinForms environment, by provided state persistance through the PostBack model. This provides an element of state to a stateless environment. In order to do this, the runtime needs to be able to have the ability to maintain this state within each "form". It does this by posting back data to itself. It's important to note that:
There is nothing really fancy about a PostBack.
It uses a HTTP form and POST, the same as any other form, from any other stack.
Just because it looks like it might be doing something special, its not, all that happens is it POST's back with some info about what caused it, so you can do things like handle client-side events, in server-side code.
So why only one?
This to me was the million pound question (I am British). I understand that ASP.NET needs this, especially if you are using ASP.NET server controls, but why the hell can't I make my own additional forms?
So, I thought screw it, just make your own form!
And I did. I added a bog-standard, simple form with a submit action of "#". This then performs a POST to the current page, with the Form data for the given form in the request.
Guess what? It all worked fine. So I ended up with:
A master page, with a HTML form in
This form posts back to the current page (basically the page using the master).
In the Page_Load code-behind for the master, I then added code to check the request to see what data was passed in the request. If it contains data (say a hidden field) then I know the post was sourced from the Form on the master page, if not, then it is most liekly a PostBack from content, and can be ignored.
I then surrounded the Content tags with <form runat="server" id="aspNetForm"...> </form> tags. This meant that all content pages automatically had a form to work with.
This provided me with a relatively simple, clean solution to my problem. My login form works fine in tandem with all the content forms created, some of which are complex forms, others use lots of server controls and many PostBacks, and so on.
I hope this helps others.
the form tag itself is in the MasterPage, as such, you can code any asp.net server controls onto the master page that you wish. And you can write up the processing logic for those server controls on the master page's code behind file.
So, in your example, you can have the login controls on the upper right of the master page, and then have the authentication logic in the code page for the MASTER PAGE, not your content page.
This allows you to have the login controls on every page, and maintain that processing, as well as maintain the content controls and their processing on their individual pages.
Everyone else has already mentioned that you can only have a single form element in a given ASP.NET page, and that it would be contained in the master page. So far, so good. But I don't think that helps you get fully where you want to be ...
In your master pages, you've (I assume!) defined asp:ContentPlaceHolder controls. Your pages which use the master then have corresponding asp:Content tags. All your page content must go in these corresponding asp:Content tags.
Once in that tag, they are part of the master page's form. The master page can respond to events from its own controls, and the pages themselves respond to events from their own controls, and you're set.
If you need the page to interact with the master page, you can access it via the Page.Master property. To interact with any publicly-visible code (methods, properties, etc.) from the master page, you'd cast this property to the correct type, and access the publicly-visible code from there.
That should get you where you need to be in this scenario. (It's worked for me on multiple sites!)
Rob,
Interesting solution. I don't see any problem with what you are doing. The problem some may encounter however, is if they try to do this with 2 server forms. There's no rule in ASP.NET that you can't have more than 1 HTML form on a page, just that you can't have more than one "runat='server'" form on the page. Obviously you've found a pretty easy way of meeting your needs.
I've found that for the most part dealing with a single form is not a problem because the ASP.NET framework basically separates everything for us with naming containers. But in your initial post comment you hit on the important factor that was absent yet critical to the essence of the original question: enter key behavior. That always throws a monkey wrench into the works.
If you were to use a standard "all encompassing" server form, couldn't you capture the right action using a textbox text changed event? Of course, if the user changed both values before hitting enter on either you would get strange behavior. And I think the core problem with the enter key is that once you have more than one submit input on an HTML form, hitting ENTER in a textbox doesn't do anything. Only when there is a single INPUT element does the enter key cause one to be "clicked".
None of the previous answers gave a code example. Here's a simplified version of the Visual Studio 2012 Site.Master that illustrates how to do this:
<%# Master Language="C#" AutoEventWireup="true" CodeBehind="Site - Copy.Master.cs" Inherits="WebApplication1.Site1Master" %>
<!DOCTYPE html>
<html>
<head runat="server">
<title>This is a title</title>
<asp:ContentPlaceHolder runat="server" ID="HeadContent" />
</head>
<body>
<form runat="server">
<header>
<div class="content-wrapper">
<div class="float-right">
<section id="login">
<asp:LoginView runat="server" ViewStateMode="Disabled">
<AnonymousTemplate>
<asp:ContentPlaceHolder runat="server" ID="AnonContent" />
</AnonymousTemplate>
<LoggedInTemplate>
<asp:ContentPlaceHolder runat="server" ID="LoggedInContent" />
</LoggedInTemplate>
</asp:LoginView>
</section>
</div>
</div>
</header>
<div id="body">
<asp:ContentPlaceHolder runat="server" ID="FeaturedContent" />
<section class="content-wrapper main-content clear-fix">
<asp:ContentPlaceHolder runat="server" ID="MainContent" />
</section>
</div>
</form>
</body>
</html>
So you have everything wrapped by a single Form element, so you can place controls in the master page, yet your content pages can also use controls.
You can only have one form on an ASP.NET page. One way to handle this is to put an event handler on the login button in the master page. The handler will validate the user and redirect to the same page on success (to correctly run the Page_Load handler, which is run before event handlers).
I solved the "clicking the return key in the login sub-form causes the main form to submit" problem in my current project by embedding an iframe into the master page. The iframe pointed to the login.aspx page which authenticated the user.
<iframe id="login" src="login.aspx" frameborder="0" enableviewstate="false" scrolling="no" runat="server"></iframe>
(form some reason I needed the closing /iframe tag otherwise design view got confused)
You can access MasterPage controls from the aspx form by:
add the detractive tag to the aspx form <%# MasterType VirtualPath="~/Site.Master %>
and in the code behind use Master.FindControl(); to get the control by ID
for Example if you want to get the
Control form = Master.FindControl("form")
now you can use the master page's form in your code.
I hope this help.
Salve! In a similar thread, I posted an answer that might help you. You can use jquery to add content to an empty div. That content can include form tags, and even a submit function independant of anything the server-side code is doing. The only downside to this is if the user does not have javascript enabled!
Instead of reposting the same answer (and the code too), here is the link:
Jquery Ajax loading form on asp.net webform
This is a limitation of ASP.NET
ASP.NET is designed to have one form per page and only one form. When it was originally designed that was not a problem.
However since then this has been identified as a huge problem with accessibility.
Microsoft Fix for this was ASP.NET MVC, if you are able to I would suggest considering moving to ASP.NET MVC as it solves a large number of problems with ASP.NET
You can have more than 1 form. (just only 1 visiable at a time) codeline 1 = form 1 visable / form 2 hidden . Code 2 Form 2 visable / form 1 hidden. = solved (this is great for static contact forms as well
no, you can only have one asp.net form per page.
That has been the rule since 1.0
They should both share the same form