document.getelementbyid('txtbox') is not working when I used in content page as it is working in the normal web page. The value is null when it is used in contentpage. Plz anybody help me
The id will have changed, you can use something like:
document.getelementbyid(<%=txtTextBox.ClientID%>).value
or you can view the source to get the id in the hopes that it will not change again.
If you have the option I'd switch to some other engine, such as asp.net mvc where you have control over the HTML.
When the page renders, if the textBox is under another control, the Id tends to change.
You can use the ClientId property:
document.getElementById("<%= txtbox.ClientID %>")
Read this article
Control ID Naming in Content Pages
ASP.NET allows certain controls to be
denoted as naming containers. A naming
container serves as a new ID
namespace. Any server controls that
appear within the naming container
have their rendered id value prefixed
with the ID of the naming container
control.
Naming containers not only change the
rendered id attribute value, but also
affect how the control may be
programmatically referenced from the
ASP.NET page's code-behind class. The
FindControl("controlID") method is
commonly used to programmatically
reference a Web control. However,
FindControl does not penetrate through
naming containers. Consequently, you
cannot directly use the
Page.FindControl method to reference
controls within a GridView or other
naming container.
Master pages and ContentPlaceHolders
are both implemented as naming
containers.
Related
Im trying to understand how the 'name' attribute works for elements in markup rendered via ASP.NET
I.e. <select id="lblxyz" name="ctl00$c$ctl341$lblxyz">
What are ctl00, c and ctl1341?
If I create a WebControl, give it an arbitrary id, then place a Button inside its Controls collection, the name attribute does not seem to reflect the container's id?
The key thing as you have discovered is that not all controls trigger this behaviour. The key is the INamingContainer interface. Only Naming Containers will contribute to the name of the control as you have seen, other controls won't.
The MSDN page linked above says it pretty well: that interface "identifies a container control that creates a new ID namespace within a Page object's control hierarchy."
The generated name attribute typically always starts with ctl00, and the rest is generated based on where the control lives in the control hierarchy. Any parent controls implementing the INamingContainer interface will contribute to the names generated for any child controls.
This may be of interest to you, it outlines out the id/names are generated: http://www.mostlylucid.net/archive/2008/11/03/way-too-much-information-on-control-ids-and-asp.net-4.0.aspx
You can control how the client ID appears using the new ClientIDMode:
All about Client ID Mode in ASP.NET 4
In ASP.NET web forms when a control is rendered on the page, the ID of each field is modified with the ctrl01 as needed to ensure collisions don't happen (aka myField becomes ctrl01$myField or whatnot).
I was wondering where one might find details on HOW the algorithm itself works, or where it might be I can find it. I am assuming the INamingContainer has something to do with this-- but alas I cannot find the part which actually decides the rendered field name.
Any help would be awesome!
You are probably looking for this msdn article.
It's based on the hierarchical layout of the webpage. But you can control this with the ClientId property.
So a textbox in a usercontrol will be named ctrl01#textboxname (Like you said in your post)
It concatenates it's own name with your original id.
In ASP.NET 4 you can suppress this concatenation and keep your own id in three different ways:
Each server control has an attribute called clientIdMode which you can set to Static
You can also set clientIdMode in the page directive which will affect all controls on the page.
Or you can set it in the web.config to affect all controls in all pages. (Unless the page or control is set to a different clientIdMode
Note: If you are using AJAX Control Toolkit you will need to set those controls that are part of the toolkit to a clientIdMode of Predictive
Apart from the other answers, if you are using ASP .NET 4, you have much more control over it.
Take a look # these web pages
http://www.west-wind.com/weblog/posts/54760.aspx
http://weblogs.asp.net/asptest/archive/2009/01/06/asp-net-4-0-clientid-overview.aspx
I am creating a web user control for a simple poll. I am currently registering it on the page and then referencing it via tagprefix.
The form for the poll is in basic html (no server controls) and is in the front-end of the web control. How can I change the look of the user control depending on the settings passed into it? Is this possible without using server controls?
Update
Can I change the html layout of a user control? If so could someone post some examples. Please note I do not use asp.net form controls, so none of that please :)
You might be able to also use jQuery to replace existing css setting in your code. Create properties on for your user control, and then pass settings in the classes. Then use jQuery to replace them. This however requires jQuery to be linked to your page (or within your control) and you'd have to write the CSS classes out to the jQuery code (using server controls, but you could use the literal control so there's no excess code).
Personally I'd go with the option of using server controls instead of straight up HTML, you'd get alot more flexibility, and then passing through the settings would be pretty straightforward, put something like this in your controls backend code:
Private _TextBoxCssClass As String
Public Property TextBoxCssClass() As String
Get
Return _TextBoxCssClass
End Get
Set(ByVal value As String)
_TextBoxCssClass = value
txtBox1.CssClass = value
txtBox2.CssClass = value
End Set
End Property
You most likely want to have a property or event in the control that changes the css. It may end up best to add some server controls or javascript / jquery to make it easier.
If its only the styles you want to change, then you can expose a property to set the style attribuites of the respective control inside your User Control. If you want to control the whole HTML layout of the control then Custom Control is the viable option.
I have a page that's derived from a master page. On this page, I have a hiddenfield ("hfUser"). How can I access this "hfUser" control and get/set its value using JQuery?
I've tried variants of this:
$(document).ready(function() {
var test = $("#hfUser").val();
alert(test);
});
but test = undefined. I'm guessing I've got the selector wrong, but I don't know how to get an asp hiddenfield. Any ideas?
Thanks
If you are using Asp.net controls, the server will mangle the control ids. It adds a bunch of extraneous control tree hierarchy information into the id. You need to reference what that acutal id is that's getting rendered, which is availble with the ClientID property on the control (hfUser.ClientID) or access your control in a different, more roundabout way, like find the controls parent, then search through its children to find your control.
If you don't have to use the asp.net HiddenField control, try just using a regular old html input.
ASP does like to mangle ID's. The further down the rabbit hole (or nesting controls) you go, the more ASP adds to your control ID. Throw in Master Pages, and it's yet another level or two.
Another way to access server-side controls (with the runat property set), is to use the square brackets in your jQuery selector.
Like this:
$("[id$='hidImgSource']").val()
That selects any elements whose ID has 'hidImgSource' as ending part of the name. So it will find mangled ID's.
Here is a link to the jQuery Selectors page that explains some more options.
If the hidden field is an ASP.NET control, check out this blog post to help you with jQuery selectors for ASP.NET controls
http://www.foliotek.com/devblog/extending-jquery-to-select-asp-controls/
Do it like this:
$(document).ready(function()
{
var test = $("**#<%= hfUser.ClientID %>**").val();
alert(test);
});
We have a win application that shows a web form in a web browser.
In order to get data from this web form we are using a hidden text box and get its text using HtmlDocument object of web browser control.
I want to make an abstraction of this web form that has this text box element so that other forms can use this abstraction.
I made a web control and put the text box on it.I thought that if I put this control on my page it would have the text box.When i ran my application I noticed that the text box had been rendered but had its control name in its name (WebControl$TextBoxName) and its id(WebControl_TextBoxName) and the win app throw an exception since it couldn't find the element by its id(TextBoxName).
So here's my question:
How can I make an abstract web form/web control that has some elements on it and I can use it to make my final forms have these elements on them? (their names and ids should not be changed)
Thank you for your help
dotNet 4.0 supports static id's so they don't get mangled, read up on Client Id Mode
Alternatively, you could override the render of your control to output a standard html hidden form field with whatever ID you want, and then also add a custom property that will return the textbox that will hide the fact that it isn't an asp.net server control.
Though I've never used the browser control in WinForms, I think what you want to use is a Master Page. Assuming what you're rendering in the browser control is an ASPX page, create a Master Page with the hidden text box that you want to grab your data from, and tell all of the pages you want to have that common control on to use your Master Page. When the page renders, the control id will then be "ctl00_TextBoxName". There is no way of getting around the ID concatenation, since unique IDs are needed and that's the only way to guarantee uniqueness with all the nested control abilities of ASP.NET. However, doing this will guarantee you always have that control named the same on every new form you create that inherits the Master Page. Hope that helps!
In summary (because who reads paragraphs?):
Create Master Page
Place your common control in the Master Page
Have your Form inherit the Master Page
You can read up on how Master Pages work in MSDN's Documentation.