I have asp.net form that contains fields. When I access this window, my javascript functions can access the fields via the DOM with the getElementById() method and when I postpack to the server I am receiving the updates made by the client.
However, when I launch the form as a child window using Telerik's RadWindow control, the javascript can not access the hidden fields on the child form. Instead I get null.
My questions are:
Are hidden fields on a child window
not accessible when the window is
launched from a parent asp.net form?
Has anyone attempted this with Telerik controls and run into issues?
EDIT
Craig pointed out that the id may be different. Two additional questions then:
Can you ensure that the id you assign at the server is actually used?
Is using getElementByName() a better mechanism to access DOM elements?
To get the ID of your asp.net control do something like this:
<%= theControl.ClientID %>
getElementByName is not as commonly used as getElementById. The ID attribute is supposed to be unique for each element on the page whereas the name attribute can be duplicated.
It is quite possible that the element's ID is not what you think it is. Check the rendered page and see if the ID is there. I am guessing that the page is given a different ID since it is rendered inside another control.
If that is the case, you can have the form render some script that returns the element ID by accessing the controls client ID.
David, I'm sending you this answer because I saw the same issue in my code, and the only REAL solution I found was that I had to support the "OnClick" function in two places... In my case, I was using PetersDatePackage, but it was on a Telerik RAD Strip.
In my case, the control was on a .ascx page, and the JS code was as follows:
function OnIncidentDateChange(ctrl, dtDate, bErr)
{
var weekday = new Array(7);
weekday[0] = "Sunday";
weekday[1] = "Monday";
weekday[2] = "Tuesday";
weekday[3] = "Wednesday";
weekday[4] = "Thursday";
weekday[5] = "Friday";
weekday[6] = "Saturday";
<%=LabelDayOfWeek.ClientID %>.innerText = weekday[dtDate.getDay()];
}
But, this itself was not enough. I had to add THIS code to my parent page. The page that holds the controls for the Telerik strip.
// Dummy function?
function OnIncidentDateChange()
{
}
Once I did that, it worked...
I'm not certain why, to tell you the truth, and it makes no sense to me, and may just be a issue with the PDP package...
I use getElementsByName for checkboxes within the same group.
As for the control's ID, TonyB has the right idea, but make sure you refer to the ClientID property in the PreRender event handler, because if you do it too early in the page life cycle, it will not be available yet).
Is it possible the that javascript is trying to get a reference to the hidden field before the RadWindow has loaded it? I believe I've run into this before and had to use setTimeout to get around the problem.
Related
I am facing issues when I tried to add same custom control twice in the same page. The issue is because instance of one control is caling the java script of the other. Added to that I am using ajax popup extender where in I have popup divs with in that control itself.
Now it is leading to java script errors because it is geting confused among the popup div ids and scripts etc.
Please help me.
Take one step further in taking care about client-side IDs generated uniquely for the tags inside each instance of your custom control.
This can be easily fixed by adding runat="server" attributes to the tags which you want to have unique client side IDs when rendered to the browser. Then you should use this kind of code in JS:
document.getElementById("<%= control.ClientID %>");
As about tags which you don't want to mark using runat attribute, you can assign them their IDs uniquely on the server-side manually in each instance of the custom control.
I hope this helps!
There's no automatic fix for this. If a custom control is going to be used more than once on a page, you have to design it to be aware of this. In particular, you'll probably need to refer to generated elements using their generated id:
var ele = document.getElementById("<%= serverSideControl.ClientID %>");
Javascript emitted by the control will have to also emit the appropriate ID's.
And so on.
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);
});
More
I have this datalist in a user control i want when i keep mouse over "More", it should be invisible. it is working on .aspx page not on user control. How to do this. This control is placed on master page.
Please Help.
Probably it will be an issue with getElementById. In a naming container you cannot get the element by simply giving its id. You have to use ClientID to get the generated id of the element at runtime.
Something like
document.getElementById ( "<%= DataList2.ClientID %>");
See Control.ClientID Property
and
Control ID Naming in Content Pages
I would agree that it's probably an issue with trying to get the id of the element since the element's id changes at runtime when you put it inside a user control. You can run your code then do a view source in the browser and see exactly what the id is generating to at runtime.
Have you tried debugging the javascript mover() and mout() function? I am guessing you are looking for elements with the wrong id's since the id's are probably different inside a user control.
I have some user controls that I want to add some client side functionality to.
Let say 1 control has a hidden field and a bunch of checkboxes. When a checkbox is checked, it sets the hidden field to 'YES'. How could I $get that control in the hosting control or page, and call some function on it that would return the value of that hidden field?
If I have a couple of these on the page, I'd like to be able to do this:
var choices1 = $get('choices1_id')
if(choices1.dirty() = 'YES')
//do whatever
var choices2 = $get('choices2_is')
if(choices2.dirty() = 'YES')
//do whatever
I might be looking for something like this: http://jimblackler.net/blog/?p=23 but I'm not sure how to access the object(s) from the parent.
thanks,
Mark
I take it the problem you are running into is that ASP.Net can mangle the id of the control?
In that case What I normally do is either note how the id is mangled for simple pages, and write the javascript accordingly, or for more complex scenarios I'll check the .ClientID property of each control and put it into variables in a custom script that's easily accessible to the rest of the javascript on the page.
This should be easier than it is, and not having simple access to every control element from javascript is one of my complaints with the ASP.Net framework. They're doing a little to address this in the next version, though not as much as they could. In the mean time, you can find various components on the web that will help automate generating the script I described above.
Is there a difference in behavior between adding a control to the ASPX page directly and loading a control programmatically and adding to a placeholder?
The control inherits from System.Web.UI.WebControls.DataBoundControl.
The reason I ask is that I have a control that works when I add it to the ASPX page like so:
...
<blah:GoogleMap ID="GoogleMap1" runat="server" Width="640px" Height="600px" ... DataSourceID="_odsMarkers" DataAddressField="Address" DataTextField="Description">
</blah:GoogleMap>
...
But not when I use the following in a codebehind page:
GoogleMap map = (GoogleMap)this.LoadControl(typeof(GoogleMap), new object[] { });
//... set properties
this.placeholder1.Controls.Add(map); //add to placeholder
Anyone have any ideas why this might be the case?
The control tree ends up the same if you define in markup or add programmatically. However there is plenty of room for the control implementor to screw up along the way.
You can go look how ASP.NET compiles the aspx:
C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files
The timing when the control is added to the page might be an issue. The usual pattern is add the control in an overload of the CreateChildControls method. If the control needs to resolve viewstate you need to make sure this is called during init, e.g. by calling EnsureChildControls.
Adding to ninja's debbugging hint. Does it make any difference if you add a label the same way. Does it show up?
Is this a user control or server control?
If it's a user control they should be loaded by their path and not their type:
GoogleMap map = (GoogleMap)this.LoadControl("~/Controls/GoogleMap.ascx");
If it's server control then you can just new up an instance:
GoogleMap map = new GoogleMap();
after you have the instance and add it to the control tree (by inserting it into the PlaceHolder) it should perform the same as when it would have been declared in the markup.
If you are setting properties outside of the LoadControl call, why are you making that new empty object array instead of just using the overload that has one parameter?
Also, if you attach a debugger to it and step through, do you notice anything weird about the control before you do your Controls.Add() call? Is there an exception being thrown? if so, which one? if not, what does the markup in the browser look like for where the placeholder is?
"Works" is kind of ambiguous, but if you mean, event handlers are never executed, you need to load it in the page onload event.
If the control requires the use of viewstate you must ensure that it is added to the page BEFORE the Page_Load event, otherwise viewstate will not be populated and most likely events and other items will not function properly.
One important difference is that if you create a control dynamically, you will not get, by default, any values from skins set. You must manually call control.ApplyStyleSheetSkin(page): http://msdn.microsoft.com/en-us/library/system.web.ui.control.applystylesheetskin.aspx