How to include javascript variable in google visualization referencing c# function

Question

There is an error when trying to include the javascript variable "selectedValue" in the c# function being called. SelectedValue has red underline error inside the GetTotalLicensesCount.

function drawExpireGauge() {

    var selectedValue = "30days";

        var data = google.visualization.arrayToDataTable([
              ['Label', 'Value'],
              ['Expiring', <%=GetTotalLicensesCount(null, null, null, selectedValue, selectedValue, null, null)%>],
              ['New', <%=GetTotalLicensesCount(null, null, null, null, null, null, selectedValue)%>],
              ['Not Used', 0]
        ]);
}

if "30days" is simply placed inside the GetTotalLicensesCount function instead of the variable, it works.

I did due-diligence and searched around the forum for a similar question but couldn't find any, please let me know how the question should be changed or if there is a reasonable duplicate that answers the question.

Answer 1

The C# code doesn't get executed as part of the js execution.

The injected C# code you have is part of a template that will generate the js code that will eventually get executed on the client. Therefore the C# code will not have access to "selectedValue".

so, C# code, gets run on the server, helps generate the HTTP response sent back to the client. JS code, gets run on client once it has the response.

You have a couple of options, Ajax back to your server to get the data, or provide all the data to js so you can write a js version of GetTotalLicensesCount.

The choice of which method depends on :-

1) how much data there is ( small, do it in js, large, ajax)

2) if any of the data needed for the calculation is sensitive and you don't want the user to see it. (always use ajax to avoid exposing sensitive data)