I don't know how to set the value of a hiddenField in Javascript. Can somebody show me how to do this?
Javascript:
document.getElementById('hdntxtbxTaksit').value = "";
HTML:
<asp:HiddenField ID="hdntxtbxTaksit" runat="server" Value="" Visible="false"> </asp:HiddenField>
error : "Unable to get value of the property \'value\': object is null or undefined"
Prior to ASP.Net 4.0
ClientID
Get the client id generated in the page that uses Master page. As Master page is UserControl type, It will have its own Id and it treats the page as Child control and generates a different id with prefix like ctrl_.
This can be resolved by using <%= ControlName.ClientID %> in a page and can be assigned to any string or a javascript variables that can be referred later.
var myHidden=document.getElementById('<%= hdntxtbxTaksit.ClientID %>');
Asp.net server control id will be vary if you use Master page.
ASP.Net 4.0 +
ClientIDMode Property
Use this property to control how you want to generate the ID for you. For your case setting ClientIDMode="static" in page level will resolve the problem. The same thing can be applied at control level as well.
asp:HiddenField as:
<asp:HiddenField runat="server" ID="hfProduct" ClientIDMode="Static" />
js code:
$("#hfProduct").val("test")
and the code behind:
hfProduct.Value.ToString();
First you need to create the Hidden Field properly
<asp:HiddenField ID="hdntxtbxTaksit" runat="server"></asp:HiddenField>
Then you need to set value to the hidden field
If you aren't using Jquery you should use it:
document.getElementById("<%= hdntxtbxTaksit.ClientID %>").value = "test";
If you are using Jquery, this is how it should be:
$("#<%= hdntxtbxTaksit.ClientID %>").val("test");
document.getElementById('<%=hdntxtbxTaksit.ClientID%>').value
The id you set in server is the server id which is different from client id.
try this code:
$('hdntxtbxTaksit').val('test');
I suspect you need to use ClientID rather than the literal ID string in your JavaScript code, since you've marked the field as runat="server".
E.g., if your JavaScript code is in an aspx file (not a separate JavaScript file):
var val = document.getElementById('<%=hdntxtbxTaksit.ClientID%>').value;
If it's in a separate JavaScript file that isn't rendered by the ASP.Net stuff, you'll have to find it another way, such as by class.
My understanding is if you set controls.Visible = false during initial page load, it doesn't get rendered in the client response. My suggestion to solve your problem is
Don't use placeholder, judging from the scenario, you don't really need a placeholder, unless you need to dynamically add controls on the server side. Use div, without runat=server. You can always controls the visiblity of that div using css.
If you need to add controls dynamically later, use placeholder, but don't set visible = false. Placeholder won't have any display anyway, Set the visibility of that placeholder using css. Here's how to do it programmactically :
placeholderId.Attributes["style"] = "display:none";
Anyway, as other have stated, your problems occurs because once you set control.visible = false, it doesn't get rendered in the client response.
I will suggest you to use ClientID of HiddenField. first Register its client Id in any Javascript Variable from codebehind, then use it in clientside script. as:
.cs file code:
ClientScript.RegisterStartupScript(this.GetType(), "clientids", "var hdntxtbxTaksit=" + hdntxtbxTaksit.ClientID, true);
and then use following code in JS:
document.getElementById(hdntxtbxTaksit).value= "";
Try setting Javascript value as in document.getElementByName('hdntxtbxTaksit').value = '0';
Related
In my aspx page, I have the following code to generate a asp:Table
abc.aspx
<asp:Table id = "_tableTest" runat="server"></asp:Table>
When I render it on the page , I need the id to be prepend with a text , for example "Address"
<table id="Address_tableTest" > </table>
How can I customize the ID generation? I couldnt find relevant documentation.
What do you mean? If some 3rd party needs the table name, then you can't change it. I mean, either you type in Address_tableTest as the ID, or you don't.
The "id" is NOT generated for you, YOU the developer type it into the markup
You can change the "id" in the forms pre-render event.
In fact, you can even change it in the page on-load event.
this.GridView1.ID = "abc";
or
GridView1.ID = "Address_" + GridView1.ID.ToString();
The "id" in markup will now thus render and use "abc".
However, code behind will continue to use "this.GridView1" to reference the control.
You can append it.
<asp:Table id = '<%# Eval("Id") + "_TableName" %>' runat="server"></asp:Table>
what is the use of Eval() in asp.net
Yes #VDWWD is correct Id can not be set dynamically
The ID property of a control can only be set using the ID attribute in the tag and a simple value. Error Generated by webforms when I tried to set it dynamically.
It is explained here in this post Eval script for server side control's ID property
I'm trying to set hidden field value in JS which I think works fine with this approach:
<asp:HiddenField ID="hfLatSW" runat="server" />
var latSW = bounds.getSouthWest().lat();
$('#<%=hfLatSW.ClientID %>').value = latSW;
I am trying to access the value on asp.net button click in code behind gives me null value. What might be happening in the postback and why am I not able to access the value set by JavaScript?
.value isn't a jQuery property. Use .val():
$('#<%=hfLatSW.ClientID %>').val(latSW);
Or without jQuery:
document.getElementById('<%=hfLatSW.ClientID %>').value = latSW;
I'm creating a modeless dialogue with the JavaScript command:-
function OpenGradeDialog(text_to_display)
{
var winArgs = new Array(text_to_display);
var winSettings = 'center:yes;resizable:no;help:no;...etc';
window.showModelessDialog('MyForm.aspx', winArgs, winSettings);
}
but somehow need to pick up the value of the supplied argument 'text_to_display' in MyForm.aspx. For preference I'd like to pick it up in the codebehind but in the .aspx would do. Does anyone know how to do this?
If you want to access it from the code-behind then you can simply add a <asp:HiddenField> to your MyForm.aspx view. For example:
<asp:HiddenField runat="server" id="hdnTextToDisplay" ClientIDMode="static" />
Populate this with your text_to_display as part of your Javascript.
You will now be able to access the hdnTextToDisplay.Value in your code-behind on postback.
Note that the ClientIDMode property on the hiddenField will stop .Net from changing the ID of the HiddenField when it renders it.
you can populate this field using javascript, so somewhere in your javascript function you can do something like this- assuming text_to_display is a string:
document.getElementById("hdnTextToDisplay").value = text_to_display;
I want to make a label invisible in child page which is defined in master page.
Is there a way to do that?
((Label)Master.FindControl("mylbl")).Visible = false;
put this in page load of the child page , mylbl refers to the ID of the label
it might be Master.Page.FindControl .... now that I think of it, it's been a while , but that's how you do it
You should use javascript. Normally in this situation, you would reference your label using
(assuming your label's ID is my_label_id)
document.GetElementById('<%= my_label_id.ClientId %>')
. . . or if you are using jquery . . .
$('#<%= my_label_id.ClientId %>')
However, AFAIK you cannot use clientid to reference a server-side control located on the master page from a content page. So I would either give the control a unique class name using the asp.net label attribute CssClass="myLabelClass" or retrieve the client Id by building the page, viewing the source, and finding the client ID. Steps for this can be found here:
How to use javascript in content page, asp.net
Once you correctly reference the item, simply change the "display" style attribute to "none" as seen below.
Using jQuery and assuming your CssClass name is myLabelClass:
$('.myLabelClass').css('display','none');
If you wanted this to occur on page load you could do the following:
$(function(){
$('.myLabelClass').css('display','none');
});
i need to do the following two things...
i want to set value of in asp .net page_load. the problem is that i dont want to use runat="server". i have tried this the following but it does not work:
HtmlInputHidden hiddenControl = (HtmlInputHidden) FindControl("a");
is there a way to access in asp .net page_load without using runat="server"? ? ?
i can do this if i use but in this case i cannot access it in master page's javascript function. i have tried this but it does not work...
var hdnField = document.getElementById('<%= hdnIdentity.ClientId%>');
var hdnField = document.getElementById("hdnIdentity").getAttribute("value");
var hdnField = document.getElementById("hdnIdentity").value
what i need... i want to access content page's hidden field value in javascript in master page. is there a way ? ? ? thnx in advance regards Haroon haroon426#yahoo.com
I sometimes do the following, especially when I want control over my ids (especially when using jquery).
<asp:literal id="literal1" runat="server"><input type="hidden" id="someid" value="{0}"/></asp:literal>
Then, in codebehind you can set the value with the following:
literal1.Text = string.Format(literal1.Text, "somevalue");
This doesn't really get around using runat="server", but you haven't specified why you don't want to do that. Also, you'd have to get the value with a request.form
Update
In .net 4.0 you have much more control over your IDs. See this for more information:
http://weblogs.asp.net/asptest/archive/2009/01/06/asp-net-4-0-clientid-overview.aspx
IIRC, you need to look in the HttpRequest.Forms, somewhere in there.
If the value is part of a POST form then you want to check Request.Forms or Request.QueryString if it's a GET form.
ad 1) in aspx file just write <input type="hidden" value="<%=GetHiddenValue%>" />. And in your code behind define protected property
public class MyPage : Page {
protected GetHiddenValue { get { /*...*/ } }
You can use it in your master page javascript how ever the control name is not what you expect it to be you'd need to use ClientID to get that. If you do not apply runat=server you can only get a hold of the control as text by either traversing the .aspx file or as some one mentioned embedding it in a named tag and then doing string manipulation on the inner HTML. That is for setting it. If you need to get the value use Request[tagName] or similar
ad 2) You can use simple html code in your content page with specified id <input type="hidden" id="myHiddenField" />. Then in master page javascript use document.getElementById('myHiddenField').