When the code var accNo = '<%=Session["hdnAccession"]%>'; will be executed ?. I change the session variable in the Page_LoadComplete event, but when I access it using var accNo = '<%=Session["hdnAccession"]%>';, it always return the value which I set FIRST. In Page_LoadComplete, I do like the following... Session["hdnAccession"] = GetNewAccession(), When I debugged, I saw that the Session["hdnAccession"] updated each time. But why it do not get updated in JavaScript ?. I am in a situation where I can not use HiddenField instead of Seession.
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what r u trying to accomplish?Arief– Arief2011-09-26 13:06:47 +00:00Commented Sep 26, 2011 at 13:06
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3 Answers
You need to create a PostBack to access session variables from JS. Like so:
<script type="text/javascript">
<!--
function setSessionVariable(valueToSetTo)
{
__doPostBack('SetSessionVariable', valueToSetTo);
}
// -->
</script>
private void Page_Load(object sender, System.EventArgs e)
{
// Insure that the __doPostBack() JavaScript method is created...
this.GetPostBackEventReference(this, string.Empty);
if ( this.IsPostBack )
{
string eventTarget = (this.Request["__EVENTTARGET"] == null) ? string.Empty : this.Request["__EVENTTARGET"];
string eventArgument = (this.Request["__EVENTARGUMENT"] == null) ? string.Empty : this.Request["__EVENTARGUMENT"];
if ( eventTarget == "SetSessionVariable" )
{
Session["someSessionKey"] = eventArgument;
}
}
}
See here: http://forums.asp.net/post/2230824.aspx
Comments
You must use some server-side control to do it(such as HiddenField or hidden span with runat="server").
<%=Session["hdnAccession"]%> will only evaluate the first time you enter the page, not during postbacks.
Comments
Your code block is getting its values when the page is rendered, and therefore any values set in Page_Load or Page_LoadCompleted should be seen properly in the client side.
If it isn't, there must be a different problem - try testing this by adding a temporary property to the page, initialize it in Page_Load and write it into the client side (i.e, var test = "<%=SomeProperty%>";).
If the problem occurs only after performing a postback (it is not very clear from your question), you will probably have to use hidden fields after all. There may be other ways to handle this, but I can't see a situation where you will be able to implement them and not be able to add hidden fields.
