So far, all the web pages I met contain at most one <form> tag. Why not multiple ones? I can not think of reasons why multiple forms can't coexist within the same web page.
Also, to be specific to ASP.NET - why are all the server controls are placed within the <form> tag? Why not place them somewhere else?
Plus,
I noticed that in an .aspx file, the <form> tag has the runat=server attribute, while a normal server control such as Button also has one. So it seems the <form> is also a server control. But strangely enough, I cannot find it in the Visual Studio Toolbox.
There can be multiple forms, with hacks.
It is indeed a shortcoming of WebForms. In ASP.NET MVC you can implement as many forms as you want (and it is valid & correct behavior of web pages).
The reason all server controls are placed inside <form> tag is to allow the WebForms engine to recognize them, load their values & save their values from/to the ViewState. Almost all infrastructure of control management in WebForms is based on the idea that a tag contains everything you access from the code-behind.
As pointed out, this is one of the shortcomings of WebForms. I do want to point out, additionally, that with cross-page posting and validation groups, you can typically reach your desired behavior (for most "multi-form" solutions).
Regarding the additional question: the <form runat="server"> is parsed as HtmlForm class behind the scenes, which inherits from HtmlControl like any other HTML element with runat="server".
Unlike any other HtmlControl though, there can exist only one instance per page and it does not appear in the toolbox as it's added automatically to every new Form you create, so it's quite pointless.
Yes, it can be done - by creating a custom HtmlForm object and toggling the forms as needed. I've just answered a similar question here (with code):
Paypal Form Ruins My ASP.NET webforms layout -> How to Solve?
many non server forms - you can , but only one runAt Server form
i also found this :
A server-side form tag is the tag which has a runat="server" attribute. If this attribute
is missing, then it's a typical HTML form tag. The conclusion is that you are allowed to use
multiple form tags on a page, as long as only one has the runat="server" attribute. The
disadvantage of the form that doesn't have this attribute, is that view state won't work
(meaning form values will disappear when using the back/forward browser buttons). It's a
small price to pay if you really need multiple forms on a page.
Take master page & set design.
Take one form in master page.
Second form take in contain place holder.
In contain place holder in only for write form tag (not use)
Add aspx page & design second form but not write form tag only for control put
Take button click event fire code write
This is proper way of two form
Related
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 am working in a CMS where we use tokens ( which is turned into a user control. Is there a way to add the user control into an attribute value for our template style?
example :
<div class="<$tokenName/$>" />
this currently outputs an encoded user control, which is then not parsed by IIS.
Short answer: this is not possible.
Longer answer...
It's not IIS's job to parse the control... that happens when IIS hands off the request to the ASP.NET engine. ASP.NET does a single-pass parse through your ASPX before the Page lifecycle even starts... this is why controls you delcare in the ASPX are available during the Init event. Whenever your CMS expands "$tokenName", you are far past the point at which ASP.NET is interpreting your markup.
If you're having trouble with that, here's a thought experiment for you: What happens when $token expands into a user control that has some other $token2 control embedded in it? And that control contains some other $token3? How many times are you going to try and parse/expand/interpret your markup?
I have the need to have 2 html forms on one page. One for login details, and one for feedback. Both forms cannot have runat="server" attrib.
Any suggestions?
Handle one of the forms as a regular HTML form -- don't use runat="server". Extract the values from any post from the Request.Form collection manually (since there won't be any server-side variables corresponding to the form).
Alternatively, put all the elements in the same form, but use different controls to submit. Each set of controls (and their submit button) should be in a different validation group to avoid having validation errors due to elements you don't care about. Handle the form processing in the callback for the submit button.
Also, I would recommend an eventual move to ASP.NET MVC. MVC is a much better architecture from the perspective of the web. It more closely aligns with the stateless web model and does not have the limitations imposed in ASP.NET to help it mimic WinForms development.
When using web forms, you should only ever have one form on the page. Probably crap, but such is a web forms world...
wrap one form around the whole page. Then when a button is clicked (or whatever event you are using) you should be able access the values of all the controls on the page.
Yes as you said, in ASP.NET you can't have more then one form element. but, you can handle more then one action in the same form. Do not use form's action attribute, use asp.net server controls like <asp:Button>, and write your logic into the event of the controls that post back.
ASP.NET page framework architecture allows single form with runat="server" attribute. You need not to worry about this thing. Place the controls on to the webform for two different purposes and handle the click events of two asp.net server control <asp:Button> separately.
You just have to split them up logically inside the one form. If you use validator and don't want the two "forms" to require the other values filled in, you have a property on the .NET controls called ValidationGroup, that just needs to be the same for all in one "form".
You won't be able to make two forms with runat="server" in one page.
Here is a nice solution
Can I have two separate forms runat="Server" in one page
though not a straight forward approach, you CAN have multiple server side forms on the same page , but it has its own limitations. Cost $50
I need to supply an html form (not a server form) for searching within an asp.net web-forms website. The form will post to another website where an indexed search is performed. Seeing as nested forms don't work well in asp.net, what is the simplest approach for this?
The nested form is a simple html form that performs a "get" against the search website, which I do not have programmatic control over.
Update: I resolved my issue by simply moving the server form to the appropriate place on the page, rather than having it surround the entire page. However, I'm still wondering how this would be handled if the html form needed to be placed physically between server controls (which require the server form).
However, I'm still wondering how this would be handled if the html form needed to be placed physically between server controls (which require the server form).
You can place controls on your page without requiring an HtmlForm.
In your case there's no issue declaring another form markup, but you could also just use some search control on your main form and make it issue a GET to that website.
Not only do nested forms "not work well," you basically can't have >1 form per page at all. The simplest approach is the approach you are forced to go with: write a page that only uses one <form runat="server"></form>. Since you need search functionality, is there no ASP.NET search box control that you could use?
Have a read here.
There are 4 workarounds:
Use an IFRAME
Force Submission to Navigate Using a GET Request
Dynamically Change the Form Action
Use a 3rd Party Form Handler
More details on http://www.revindex.com/Blogs/tabid/65/EntryID/21/Default.aspx
Nested forms don't work well in HTML full stop! You should never do it.
Perhaps you mean more than one form on page? Whilst it's true you can only have one form with runat="server", I can't see any reason why you couldn't have a standard form (not server form) that posted to another site at the same level (ie. not nested).
Try adding your HTML input elements to wherever you want the nested form to be. Then use JQuery to change the page form action to point to the external Website. The entire form is submitted, but with a different external Url. The minor downside is the values for all input elements on the page are posted, but most times that is not big deal.
(I only tried this using a POST, not a GET. This is basically Roman O's #3 workaround in more detail)
<div id="nested-form">
<input type="text" name="q">
<input name="searchbtn" value="Go" type="submit" class="search-button">
</div>
<script>
$(function() {
$("input.search-button").click(function() {
$('form').get(0).setAttribute('action', 'http://external.com');
});
});
</script>
maybe you try Server.Transfer() to your target page that do the search from a button for example!
I have a simple website and I use masterPage for designing my template.
everythings work fine, but when I add a Custom (google) Search Box in it my pages correpted.
infact asp does not support Nested Form and as you all know google use a simple form to get queries from the users.
so at first I redesign my site and put 2 Form in it. One server form for my pages content and one other form for google search box. untill here everything work fine .
so I force to add 2 new button beside of my search box and these buttons need a runat=server form, so now I need an approach that let me enable a third form (second runat=server form ) or find an approach to use simple form inside of runat=server form, actually
howcan I put 2 form inside each other or how could we enable a nested form ?
Nested forms won't be possible. You'll need to make those buttons work without being in a runat="server" form.
Cause Asp Forms are not a display control and just accessible in code for programmers,
so I use it in a unregular manner,
as you all know every XML markup like XHTML (asp) have some element (in asp case : control) and each element have its own attribute (in asp case controls properties)
so I just need to put my controls inside the Form (root) Element and cause when page loading on client machine, whenever browser see the server form just change a flag to true (the server form is available) then you can use what ever you have inside of the form,
so if you can lagically put your controls inside of the form , so putit, nothing bad happen )