When don't you need to use runat="server" in ASP.NET?
EDIT: Thanks for all the answers, but I was really thinking of runat="server" inside an <asp: tag.
Use the runat=server attribute when you're using ASP.NET controls, and/or you require programmatic access to those controls in your code-behind.
HTML controls don't require this attribute. It's useful if you have any HTML element like <span> <div>, or <table> when you want the ability to access them in code-behind.
<asp:Label runat="server" id="foo" />
<div runat="server" id="bar />
...
foo.Text = "Hello Label";
foo.Attributes["class"] = "baz";
You need to use runat="server" on any control that you want to be parsed as a server control.
Any element with runat="server" will be parsed into a server control in the Page herarchy. Anything else will be handled as plain text, and put in LiteralControl controls in the Page hierarchy.
The exception is elements that aren't real elements, but special tags within another server tag, for example ContentTemplate tags. They don't need a runat="server" because the containing control will parse them.
When you don't want the server side ASP.NET to render a server side variable against us.
Generally speaking you don't use it when you don't need to manipulate the DOM element at the server side e.g. which are only used for layout purposes.
Without runat="server" there would also be no other way to make html controls server side controls. It does look like an odd thing, because you can't do runat="client".
So in summation you can't leave it out on any ASP .Net controls ever and it was probably the easiets and cleanest way to find all server side controls for the developers who created ASP .Net Web forms.
source: http://mikeschinkel.com/blog/whyrunatserverforaspnetpart2/
Tag runat="server" indicates that the code contained within the script block will run on the server (and not on the client). On execution, ASP.NET will create server-side objects that contain this code as well as an instance of the Page class to contain the controls defined inside the page as instances of their given type (System.Web.UI.WebControls.Textbox, for example). This server-side object will be invoked on user request and will execute code in response to events.
Create Control in Runtime
I need one label in runtime that time don't need runat="Server" is not required
Example
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
Label lblNew = new Label();
lblNew.ID ="lblnew";
lblNew.Text ="Test";
}
}
this code create label in runtime at page load event
Related
I went through this thread but couldn't understand much. I am very new to ASP/HTML/Server-side programming.
I tried running this code on a .aspx file:
<form id="form1" action="Default.aspx">
<div>
<asp:Label ID="lblName"></asp:Label>
</div>
</form>
And I got an error when I tried to use this in the CodeFile:
protected void Page_Load(object sender, EventArgs e)
{
lblName.Text = "123";
}
"lblName does not exist".
But if I use runat="server" attribute with the label, then this code works.
Also, is there any concept of nesting the runat attribute. e.g, If I specify runat=server for the form above, will all my controls inside the form automatically be configured to run at server? How does this attribute work?
In which case would I be required to specify runat=server for the and for the tag? How does the server-side know that the label is inside the form if I don't have a form object at server side? Or am I missing something?
Any element marked with runat="server" lets the framework know that this will be a control on the server side. This article has more details:
Exploring the Runat Attribute
Nope, there is no such nesting available in ASP.NET, you have to specify "runat" to every control that you want to use in code behind and that is part of ASP.NET web library.
Because ASP.NET can only recognize difference between client side tag (the html that runs on browser) and server side tag with help of "runat"
iam using aspx date edit control in my asp.net and c#.net application.
is it possible to disable aspxdateedit control in javascript?if so how acan that be done.becoz ,i tried
using
"document.get elementbyid("datedit").disabled=true;"
but it didn't worked out !!
any suggestion on this?
This can be done using the editor's client side SetEnabled method. I.e.
// JS
dateEdit.SetEnabled(false);
Note, here the dateEdit is the editor's ClientInstanceName property value. It allows you to define the name of the java script client side object. Using it, you will be able to access its client side properties and methods.
First of all set the control's ClientInstanceName property to access the control at client side.
<dx:ASPxButton ID="btnSubmit" runat="server" Text="Save" AutoPostBack="false"
Width="120px" **ClientInstanceName="btnSave"**><ClientSideEvents Click="OnButtonClientClick" />
</dx:ASPxButton>
Now you can do this in two ways as:
ClientSideEvents Click="function(s, e) {document.getElementById('btnSave').enabled = false;}"
Have can try this also:
ClientSideEvents Click="function(s, e) {btnSave.SetEnabled(false);}"
you can also access these controls in javascript code at aspx page either in a callback event or some other client side method.
just access the control with their associated client instance name as i have btnSave for my ASPxButton
btnSave.SetEnabled(false);
get more information about these control's methods and client events etc. see the clientscript namespace of these aspxEditors DevExpress.Web.ASPxEditors.Scripts Namespace
hope you will get your solution or help to solve your problem here..
Happy Coding..
I use ASP.NET and have a label control on my page, which I fill with
the jQuery-Command
$('#<%= myLabel.ClientID %>').html(content);
.val() does not seem to work with this.
Somehow, I have Problems getting the content in code-behind. In the code, the myLabel.Text-Property is still empty.
If you want to display the value on the client and have it available on the page, you need an input that'll get sent to the code-behind when you POST like this:
$('#<%= myLabel.ClientID %>').html(content);
$('#<%= myInput.ClientID %>').val(content);
<asp:Label Id="myLabel" runat="server" />
<asp:HiddenField ID="myInput" runat="server" />
In the code-behind:
myInput.Value
I think your problem is that labels (rendered as span tags) are inherently read-only in the asp.net world. They're not meant to be used as 'input' controls, and as such changes to their HTML on the client-side are ignored on the server-side, where values are set based on ViewState.
To do what you are asking, you'd have to notify the server of the change as well, such as by using AJAX. The only issue here is ajax webmethods in your code behind are static, and because of this can't access the page's control set to change the .Text value.
In the end the easiest option is to make use of hidden fields as Nick said. These are technically 'input' controls and their values changed on the client-side are sent to the server as you desire. You'd just have to keep the label/span and hidden field/input synchronized on the client.
Hope this helps.
What is the difference in functionality between
<asp:Button id="button1" Text="Click me" runat="server" OnClick="submitEvent" />
and
<input type="button" id="button1" runat="server" value="Click me" />
Does the input with runat="server" attribute has other or limited properties and methods?
Thank you!
The first one creates a System.Web.UI.WebControls.Button while the second one creates a System.Web.UI.HtmlControls.HtmlInputButton.
Both are server controls, but the controls in the WebControls namespace generally has a bit more functionality than the controls in the HtmlControls namespace. Typically they put some data in ViewState to keep track of their state, and they have server side postback events.
Each controls in the HtmlControls namespace correspond exactly to an HTML element, while the controls in the WebControls namespace may be rendered differently depending on what the browser that is requesting the page can support.
The button represented by <asp:Button runat="server".../> will be converted to a web server control with a rich state model and different properties and methods which has more clear representation in real world like Button.Text = "Click Me".
The button represented by <input type="button" runat="server"..../> will be converted to html server control represented by HtmlInputButton; with has limited properties, methods and events. Most of the properties resemble the html equivalents like Button.Value="Click Me".
Note that elements in a markup page are pre-processed/compiled before being used and will be converted to a class representation where every element is represented by a control. You can access server side controls which are identified by the runat="server" tag from the code behind since they will have the correct matching server control(web/html), other static content including an <input type="button.../> tag with out the runat="server" will be represented as a LiteralControl.
The former line is ASP.NET, the latter simple XHTML.
The former gets parsed and interpreted on the server side, after which the HTML code is generated, which pretty much corresponds to your second example. The ASP.NET Button is really little more than light wrapper over th HTML input button functionality, and should be used wherever you need to handle the Click event on the server side (or in the general case any events), and is usually the way to go, since you're letting ASP.NET abstract the idea of a button on your page for you.
functionality of both the controls is same with the difference that first one is .net control and second one is html control that can be made servercontrol by using
runat="server".
and first one is rich in evants and metods thn the second one....
There is no server events associated with such a controls, but you can use it in codebehind to change it's properties.
Your second option won't probably even work. runat="server" will be rendered directly to the HTML output where it will have no functionality and will only break HTML validation.
input is an HTML element which has only HTML properties, and definitely no methods of any kind.
I need help on this following aspx code
aspx Code:
<asp:Label ID ="lblName" runat ="server" Text ="Name"></asp:Label>
<asp:TextBox ID ="txtName" runat ="server"></asp:TextBox>
Consider this is my aspx page content. I am going to populate the values for the TextBox only after the postback from server. But the label is also posting to the server (runat="server") even though it's not necessary. Should I write my code like this to save time from server with less load.
Corrected Code:
<label id ="lblNames">Name</label>
<asp:TextBox ID ="txtName" runat ="server"></asp:TextBox>
Only my server control will send to the server for postback and not my HTML control which has a static value.
Please suggest whether this is the correct way of coding.
If you take the runat='server' out of the <label> element then it won't be parsed as a server control. If you're not going to do anything with lblNames from the server then it is perfectly okay to leave it out.
If you're not doing anything with the label server-side, then just use a <span>. It'll end up as the same html at the browser.
.net label controls are rendered as html label elements and do not get posted back to the server. Labels just don't post back. The server control allows you to manipulate the properties of the control in code however which is very useful.
There is nothing wrong with using html tags as well in your aspx/ascx page though if you don't need any programmatic control of the element.