How to update the session values on partial post back and how to make Javascript use the new values
- by Mano
The problem I am facing is the I am passing values to javascript to draw a graph using session values in the code behind. When page loads it take the value from the session and creates the graph, when I do partial post back using a Update Panel and Timer, I call the method to add values to the session and it does it.
public void messsagePercentStats(object sender, EventArgs args)
{
...
if (value >= lowtarg && value < Toptarg)
{
vProgressColor = "'#eaa600'";
}
else if (value >= Toptarg)
{
vProgressColor = "'#86cf21'";
}
Session.Add("vProgressColor", vProgressColor);
Session.Add("vProgressPercentage", "["+value+"],["+remaining+"]");
}
}
I use the update panel to call the above method
<asp:ScriptManager ID="smCharts" runat="server" />
<asp:UpdatePanel runat="server" ID="Holder" OnLoad="messsagePercentStats" UpdateMode="Conditional">
<ContentTemplate>
<asp:Timer ID="Timer1" runat="server" Interval="5000" OnTick="Timer_Tick" />
and the timer_tick method is executed every 5 seconds
protected void Timer_Tick(object sender, EventArgs args)
{
ScriptManager.RegisterStartupScript(this, this.GetType(), "key", "r.init();", true);
ResponseMetric rm = new ResponseMetric();
Holder.Update();
}
I use ScriptManager.RegisterStartupScript(this, this.GetType(), "key", "r.init();", true);
to call the r.init() Java script method to draw the graph on post back and it works fine.
Java Script:
var r = {
init : function(){
r = Raphael("pie"),
data2 = [<%= Session["vProgressPercentage"] %>];
axisx = ["10%", "20%"];
r.g.txtattr.font = "12px 'Fontin Sans', Fontin-Sans, sans-serif";
r.g.barchart(80, 25, 100, 320, data2, { stacked: true, colors: [<%= Session["vProgressColor"] %>,'#fff'] });
axis2 = r.g.axis(94, 325, 280, 0, 100, 10, 1);
}
}
window.onload = function () {
r.init();
};
This Java Script is not getting the new value from the session, it uses the old value when the page was loaded. How can I change the code to make sure the JS uses the latest session value.
