I have an control1.ascx page
and control2.ascx page
both of them have this element:
<asp:TextBox runat="server" ID="txt_name" ClientIDMode="Static"></asp:TextBox>
page.aspx contains both of the controls.
so now the page contains input type text with the id "txt_name" X2.
I am wondering how it is working? can someone explain?
Ideally, you want to use ClientIDMode="Static" only if you are sure that no other control has same name in the page.
For example, you really want to access the ServerControl from external javascript file (althought it is not a good design).
If you are not sure, you want to use Predictable.
As your are using ClientIDMode="Static" thus control's id will be rendered exactly as it is.
ID will be rendered directly. See MSDN docs, this Blog is a good read.
ASP.Net 4+ supports various modes to generate ClientIDs for controls.
Here is a reference for MSDN on ClientID and its' generation modes: http://msdn.microsoft.com/en-us/library/system.web.ui.control.clientid(v=vs.100).aspx
To see how ClientID generation works, you may want to refer to this link :
http://www.codeproject.com/Articles/108887/Client-Ids-Generation-with-ASP-NET-4-0
(It has visual explanations on how the ClientID generation works in different cases)
Hope this helps.
Situation: I have been creating webpages in HTML5/CSS3 & Javascript using Sublime 2 text editor for a year, however a college course now requires me to use Asp.Net and Visual Studio 2010. I do not use the designer because I am proficient at doing things by hand, however I find that writing asp: inside every element is time consuming and causes syntax errors when applied to some HTML 5 tags and not others.
Example HTML 5: <button id="btn" type="submit" value="Button"/>
Example Asp.net: <asp:Button ID="Button1" runat="server" Text="Button" />
Question: Can the asp: portion be omitted without effecting anything or is it required for IIS or the C# back-end functionality? What about runat="server" can that be omitted?
Google has come up dry regarding my inquiry, so any help is appreciated.
you simply cannot remove either of the two
but hear me out why, because I have a feeling you are not familiar with ASP and therefor are mistaking the meaning of the asp: and the runat="server" syntax.
first: runat="server"
this property on an element, tells the the compiler that this is actually a server side control
so a <button/> is not the same as an <button runat="server"/>
the first one is pure html, while the second one is a control, which can be bound to on the server side. .Net will give it a clientID (not to be mistaken by the ID you have to give it yourself).
second: asp:
this is a prefix, on certain elements, that tells the compiler these are ASP controls (the default controls given by the ASP.net framework). These include Buttons, TextBoxes, DropDownLists, ...
do not mistake 1 of these with a html element.
an <asp:Button id="myAspButton" runat="server"/>
is not the same as a <button id="myHtmlButton"/>
the first, is a server side control, which can be bound to (see it's runat="server" attribute), and this control renders to the browser as a <input type="submit"/> for example.
you could alter the rendering of the asp.net button class to make it return something entirely differnt if you wish.
and you are also not limited to using asp.net classes.
you can create your own controls, and put them in a custom created library
you could give those your own prefix.
if I created such a custom control, I could register a prefix for it in the web.config file,
and thus I could create a custom button extending from the original one (but with a default label in front...
<myc:CustomButton ID="myButton" Text="myButton" Label="myLabel" runat="server"/>
which could render into:
<label>myLabel</label>
<button ID="*******">myButton</button>
the asterisks are symbolizing the Unique ID it will get from the .net framework
if you want to know more on custom controls, or extending default controls
here is a step by step explanation to create custom controls, or extend from a TextBox control.
it also shows how you add a custom prefix for your controls (in the this case 'cc')
you can find more info here
The runat="server" part is required to tell .NET that it will have to render a button there (which will contain .NET specific ID for processing upon POST). Not too familiar with web forms (I started with MVC), but I would assume that the asp: part is to help distinguish between server controls and standard HTML markup.
Why not try removing it and if it breaks something, then you know it's needed. For instance if the button doesn't show up after removing it, then obviously the .NET markup parser needs it to be there in order to know that it is a place holder for a server control.
If I have a TABLE or a DROPDOWNLIST, with an ID="Test", in a Page Default.aspx, contained in a Master Page, these controllers change their ID's to "MainContent_Test", means any CSS attributed to #Test won't work, and I feel that I'm having problems in C# as well, why does this happen? and How can I prevent it?
If you are using asp.net 4 and above you can set the ClientIdMode of the control
This will ensure that it won't change and can be assessed via css.
<asp:DropDownList ClientIdMode="Static" ID="Test" runat="server"/>
ASP.NET adds name of control containers to generated client ID. But if you use .NET 4.0 or later you can use cotntrol's ClientIdMode property:
http://msdn.microsoft.com/en-us/library/system.web.ui.control.clientidmode(v=vs.100).aspx
Just set it to Static and the ID will not change.
Other options may include defining style via class and not attaching it to specific control ID.
Given a textbox:
<asp:Textbox runat="server" id="txtAddress1" />
This renders as something similar to:
<input name="ctl00$mainContent$txtAddress1" type="text" id="ctl00_mainContent_txtAddress1" />
I don't think browsers autocomplete features recognise this name/ID as a field they can autofill, they are not standard recognised names.
Is there any way to overide the client ID's so that autocomplete has a better chance of recognising them?
2 Points with this.
1) The "Override the Name" feature was introduced in ASP.Net 4.0, where for any property you can choose a hardcoded name instead of the dynamic name. You need to be careful on this as you don't want 2 objects sharing a name.
2) ASP.Net 2.0 and above (may have been in v1.0) has a property on the control called "AutoCompleteType" which provides a hint to the browser on what sort of information is required in the box.
Assuming you're using Asp.net 4.0, and you're aware of the points mentioned by DJIDave, you can use the ClientIDMode property on a control, and set it to 'Static'. Then, what ever you specify in the Id field in Asp.Net will be brought through to your final markup, and will not be 'mangled' (for want of a better word) by Asp.Net.
I have this label control in my web page
<asp:Label ID="Label1" runat="server" Text="test"></asp:Label>
And when the page rendered the id of the control changes to something like this
<span id="ctl00_ContentPlaceHolder1_Label3">test</span>
How can I stop asp.net from changing IDs in order to perform a jQuery operation like this
$('#label1').html(xml);
Short answer:
Set ClientIDMode="Static"
<asp:Label ID="myLabel" ClientIDMode="Static" runat="server" Text="testing"></asp:Label>
Long answer:
.NET 4 now has the ability to let you choose your ClientIDMode:
Type: System.Web.UI.ClientIDMode
A value that indicates how the ClientID property is generated.
AutoID
The ClientID value is generated by concatenating the ID values
of each parent naming container with the ID value of the control. In
data-binding scenarios where multiple instances of a control are
rendered, an incrementing value is inserted in front of the control's
ID value. Each segment is separated by an underscore character (_).
This algorithm was used in versions of ASP.NET earlier than ASP.NET 4.
Static The ClientID value is set to the value of the ID property. If
the control is a naming container, the control is used as the top of
the hierarchy of naming containers for any controls that it contains.
Predictable This algorithm is used for controls that are in data-bound
controls. The ClientID value is generated by concatenating the
ClientID value of the parent naming container with the ID value of the
control. If the control is a data-bound control that generates
multiple rows, the value of the data field specified in the
ClientIDRowSuffix property is added at the end. For the GridView
control, multiple data fields can be specified. If the
ClientIDRowSuffix property is blank, a sequential number is added at
the end instead of a data-field value. This number begins at zero and
is incremented by 1 for each row. Each segment is separated by an
underscore character (_).
Inherit The control inherits the ClientIDMode setting of its NamingContainer control. This is the default.
instead of using this selector
$('#Label1')
use this one, basically you are using the classic asp inline server side code.
$('#<%= Label1.ClientID %>')
this will insert whatever ID that is generated to be placed as a literal.
If you wish to use external files then I would suggest you create an obj that is global on the page to hold all of your client ids and then reference that obj within your external files (not ideal but it is a solution)
var MyClientIDs = {
Label1 = '<%= Label1.ClientID %>',
Label2 = '<%= Label2.ClientID %>',
Textbox1 = '<%= Textbox1.ClientID %>',
Textbox2 = '<%= Textbox2.ClientID %>'
};
and then in your external file you can access Label1 for example: $('#' + MyClientIDs.Label1)
In .NET 4+ set ClientIDMode="Static". This will solve your problem.
Example:
<asp:Label ID="Label1" ClientIDMode="Static" runat="server" Text="test"></asp:Label>
You can't stop asp.net from generating those IDs. That's just how it does things.
You can still use jquery like so:
$('#<%=label1.ClientID %>').html(xml)
or
$('[id$=_label1]').html(xml)
If and only if you're container layout is never going to change and you require to put your JavaSctipt/jQuery in an external file, you could use the generated ids within your jQuery selectors i.e.
$('#ctl00_ContentPlaceHolder1_Label3').html(xml);
Obviously, this approach requires you to find out what the generated ids will be and requires caution if you ever start changing the site/application construction.
Otherwise, your best options are
1. Use the inline server side code markup. The downside to this approach is that you cannot put your js code in an external file -
$('#<%= Label3.ClientID %>').html(xml);
2. Define unique CSS classes on each control you need to use in your jQuery, which would still allow you to put your js code in an external file -
<asp:Label ID="Label3" runat="server" Text="test" CssClass="label3">
</asp:Label>
$('.label3').html(xml);
3. Use jQuery selectors to pattern match the original id, which again, would allow you to put your js code in an external file -
$('[id$=Label3]').html(xml);
This jQuery selector will select all elements with attribute id whose value ends with Label3. The only potential downside that I could see with this approach is that in theory, it could be possible to have a Label control with id Label3 in say, a Master page and also in two content pages. In this example, using the jQuery selector above would match all three labels, which may have unwanted consequences.
EDIT:
I thought it might be useful to raise your attention to the IDOverride control. An Example page can be found here
It allows you to specify which controls should have their mangled id within the outputted HTML markup overridden with the id as is given in the .aspx file when rendering out the HTML page. I have only played with it briefly with a single Master Page and Panels, but it appears to work well. Using this, you could use the original ids within your jQuery selectors. Be aware however, that the results are unpredictable if you were to have controls with the same ids in your Master page(s) and Content page(s) that are combined to render the HTML for one page.
Short answer, don't worry about using the asp.net IDs. In asp.net you can add your own attribute to a tag:
<asp:TexBox ID="myTBox" runat="server" MyCustomAttr="foo" />
Then in jquery you can refer to this element via:
$("input[MyCustomAttr='foo']")
I do this all the time with jQuery. Hope it helps.
You can call a class name rather than using an ID
For example;
$('.CssClassName'). ...
Or if you type this in the MasterPage's very first line, your control IDs won't change :
ClientIDMode="Static"
For example;
<%# Master Language="C#" AutoEventWireup="true" CodeFile="MasterPage.master.cs" Inherits="Main_MasterPage" ClientIDMode="Static" %>
The inline code is the correct way to do it. However this will be changing in ASP.NET 4.0. We have spent some time adding a feature that allows full control of the IDs that are generated client side. Below are some resources on the web about this feature.
http://blog.osbornm.com/archive/2009/01/06/asp.net-4.0-clientid-overview-again.aspx
http://channel9.msdn.com/shows/10-4/10-4-Episode-3-ASPNET-WebForms-40/
Most of the suggestions here will work, but test results on jQuery code show that pure ID selectors are by far the fastest. The one I use most often:
$("[id$=origControlId]")
is pretty slow, but the problem isn't too apparent unless the page has many controls and a lot of jQuery.
Since is it fairly painless to assign multiple classes to a control, you could give each one a CSSClass that matches the ID. Since they would then be unique (you'll have to watch repeater type controls that generate multiple controls), you could select by class.
For example:
<asp:Label ID="Label1" CssClass="Label1 SomeOtherClass" runat="server" Text="test">
</asp:Label>
could be selected uniquely by:
$(".Label1")
Which is almost as fast as an ID select.
I had never considered this one:
$('#<%= Label1.ClientID %>')
but I'm going to try it!
You have to pass the control's ClientID to the javascript code (I doubt though that Label1 gets renamed to Label3)
ClientScriptManager.RegisterClientScriptBlock(GetType(), "someKey",
"$('#" + Label1.ClientID + "').html(xml);", true);
You can use the ClientID (just like everyone else said) but the problem with that is that it cannot be used in an external JavaScript File.
So, ideally, instead of using the ID to reference it from jQuery, use a CSS class:
<asp:Label ID="Label1" runat="server" Text="test" CssClass="myclass"></asp:Label>
Then you can reference it like such:
$(".myclass")
You can override the ClientID and the UniqueID as this fella did.
/// <summary>
/// Override to force simple IDs all around
/// </summary>
public override string UniqueID
{
get
{
return this.ID;
}
}
/// <summary>
/// Override to force simple IDs all around
/// </summary>
public override string ClientID
{
get
{
return this.ID;
}
}
You may also create a custom control that inherits from Label that overrides the ID property to be what you want it to be.
This can be achieved by replacing the asp.net id with the original id as the control is rendered.
This is pretty easy and can be donw by creating a set of custom controls.
http://www.bytechaser.com/en/articles/ts8t6k5psp/how-to-display-aspnet-controls-with-clean-id-value.aspx
At the risk of being patently obvious change:
<asp:Label ID="Label1" runat="server" Text="test"></asp:Label>
to
<Label ID="Label1" Text="test"></Label>
You need to put the property ClientIDMode="Static" in your button, this grants the ID will be the same in runtime, it's what you need to get object in Javascript.
you don't need to "prevent" asp.net from changing the control id in order to use jquery, or javascript at all for that matter.
the id that gets rendered on your page is the ClientID property of the control and what you're setting on the control itself is the ID. you can't set the ClientID property, it's generated for you and may or may not be the same as your ID. however, as others have mentioned you can use the ClientID property either in your aspx:
$('<%= Label1.ClientID %>').html()
or by registering the client script in your code behind file using one of the ClientScriptManager methods.
Just get rid of the placeholder. Or select by class or DOM hierarchy. Or even use partial matching on the ID as a last resort. There are many easy, clean ways to select an element in jQuery, we need to wean ourselves away from our old, ugly ASP.NET habits.
And Dreas Grech put the final nail in the coffin. You can't use use external script files with the $('#<%=label1.ClientID %>') type solutions.
Mike
You still can use PlaceHolders and set ClientIDMode in the PlaceHolder tag :
<asp:ContentPlaceHolder ID="BodyContent" runat="server" ClientIDMode="Static">
</asp:ContentPlaceHolder>
None of the contained controls IDs will be altered.
Simple, with overriding the control class. Here is an example with an HtmlGenericControl but you can do it with any ASP.Net control:
public class NoNamingContainerControl : HtmlGenericControl
{
public NoNamingContainerControl(string tag) : base(tag) { }
public override string ClientID
{
get
{
return this.ID;
}
}
}