i want to know that why we use code behid approch. if there is some advantage then plese share to me ? as we know that there is two methode for writing server side code for
aspx.file
code-behind approch in which we usually we seprate our server code aspx.cs file from aspx file
we can directly write server side code in aspx page by writing //server side codebefore html tag ?
so i wnat to know that is ther any authentic reasion which provide advatage in code-behind approch.
You should strive to separate UI layout from UI or business logic. Those who use codebehind benefit from the advantages of compile-time warnings, type safety, and better debugging support.
Check this article - https://web.archive.org/web/1/http://articles.techrepublic%2ecom%2ecom/5100-10878_11-1049844.html
EDITED: this one is helpful too to give information of code-behind pages -
http://www.java-samples.com/showtutorial.php?tutorialid=1084
It helps prevent spaghetti code with a mix of markup and code, which is hard to maintain and review.
Related
Could I declare asp.net page method in side Web form code behind file using [System.Web.Services.WebMethod] attribute?
Yes, you can add the code inline if you want - it's pretty messy though. Take a look at this blog post for help. Also, take a look at this MSDN reference for a comparison. There is also another tutorial here.
In my opinion, if you need to use webforms, then you should stick to the code behind model and keep the minimum about of code in there for the event handlers only. Move any business logic, or utility code into separate classes.
I am trying to use a checkbox that is dynamically declared in an .vb file that I am trying to write into my .aspx page. I am able to write a normal checkbox of <input type='checkbox /> from the .vb Class using Response.write, but it comes up blank when using <asp:Checkbox runat='server' />I need to pass whether or not the box is checked back to the server, because I am having to either approve something if one is checked, reject something if the other is checked or do nothing if neither are checked. I have figured out how to make them mutually exclusive either way so that is not the problem. Does anyone have any recommendations?
Your problem lies in the order that the pages are compiled in: When you place an asp control like the asp:checkbox, it is compiled into a regular checkbox with some javascript attached when it is sent over to the client.
When you write the string "<input type='checkbox />" to the page from the code-behind it is writing that string directly to the page, after the aspx page has compiled its controls, but since that is valid html the browser renders the control. When you write the asp:checkbox, the browser doesn't know what to do with it, because it is not valid html. In addition, the page has already been compiled, so there is no chance of .net creating the correct control for you.
You need to programmatic add the control to the webpage by creating a new control through the code behind
This site does a great job explaining it
And #toodles seems spot on. Writing static html and asp.net are two totally different ball games. I would spend a bit of time (like hours/days) reading/watching learning material to help you get on your feet.
The technical answers you are getting are all good. However, your question indicates that you really need to start by learning how asp.net server controls work. I suggest spending a couple hours watching the videos at http://asp.net and particularly http://www.asp.net/general/videos/intro-to-aspnet-controls
Then focus on understanding the page lifecycle and you'll have enough of the basics to be much more effective at asp.net. Have fun!
You can't use response.write to create server controls.
See this site for an example of the right way to do it:
http://msdn.microsoft.com/en-us/library/kyt0fzt1.aspx
I am utilizing controls in my asp.net application. I have a register tag the source of which needs to be dynamic. I am using the line below which functions correctly when the full path is specified but when I change it to the variable I get a parser error. Any idea how I can go about doing this?
Thanks
It might be better to use Load Control from the code behind of the aspx page.
If I'm understanding you correctly — you can't use a variable in those directives (Page, Register, etc). They have to be constant expressions.
However, it is possible to dynamically load ASCX controls. You would have to do this in code, though, and it would not involve the Register tag.
I've got an ASP.NET 3.5 Web Forms application in which a large chunk of code needs to be duplicated between a few different pages. Sounds like the ideal candidate for a user-control right? Problem is, this cannot be contained within a <form runat="server"> because it contains a client-side form of it's own.
There are no runat=server controls or postbacks or anything that really need that webform - think of it just as a chunk of HTML with a few basic <% %> tags. I'd just want to set a property on the control when it's loaded, so that it knows what to output. This is purely an exercise to make the code easier to maintain.
Before I resort to using an oldskool <!--#include-->, is there some better way of doing this?
You can still use a normal user control. Just don't rely on viewstate and postbacks and you shouldn't have any problems.
<%=Response.Write(File.ReadAllText(Server.MapPath("~/includes/filename.ext")))%>
Something along those lines, anyway.
Edit: Same functionality as a server side include, but if I'm not mistaken, enabling the SSI syntax requires an IIS change, where as this wouldn't.
Edit 2: I didn't see the note that your include contains asp.net code. This would obviously only work for client side code only. My mistake.
You can have as many form controls as you want but only one can have runat="server".
Some other techniques:
http://webproject.scottgu.com/CSharp/UserControls/UserControls.aspx
http://weblogs.asp.net/scottgu/archive/2005/08/28/423888.aspx
I'd still make it a control. The <% %> stuff could be labels/literals for more flexibility, and as soon as you get done saying there are no postbacks needed, you'll need them. Best to set up the other pages to include it as a control now for easier changes later. Heck - you could even take advantage control-level caching!
I am looking to make a web control where I can register client startup scripts inline with my aspx because I hate registering in the codebehind!
An example of what I have so far:
<Ben:StartupScript runat="server">
var form = document.getElementById("<% =form1.ClientID %>");
</Ben:StartupScript>
Currently, I am overriding the OnPreRender method of the control, rendering the contents of the control to a string and then manually registering that string as a startup script using ClientScript.RegisterStartupScript on the Page. I also override the Render method in order not to render the control. I should also note that I have the ParseChildren attribute set to false and the PersistChildren attribute set to true.
All seems to be working well, but my control allows other web controls inside it (such as Button). Apart from being unintuitive, this can result in runtime errors. I would love to be able to clear the controls but this is impossible given the <% ... %> code block.
So, is it possible to prevent developers from embedding child controls whilst still allowing code blocks?
Also, is this idea any good or is it fundamentally flawed? Lol.
Thanks a bunch,
Ben
it sounds like a good idea, but if you spend too much time fighting the inherited/default behaviors then it may be more trouble than it's worth
if this is a one-shot issue, a cheap-hack solution is to just directly embed your scripts in the header of a master page ;-)
on the other hand, allowing developers to embed their own scripts as children of your web control might be useful
If you are using master pages, add another control in your section. That way you can easily add css/js to your headers in your child pages.
ClientScript.RegisterScript is mostly for user/server controls,