Problem to access .net variables via JavaScript!

Hi

In my view, i want to access some of my code behind variables which stored in TempData. To do this, i've using this code for my view & scripts :

@model DefaultVisitProductHeaders<div class="row"><div class="col-md-6"><form id="frmNewPackageHeaderItem" asp-action="Create" method="post"><div asp-validation-summary="All" class="text-danger"></div><input type="hidden" id="hdnDefaultVisitProductHeaderRowID" asp-for="DefaultVisitProductHeaderRowID" value="" /><div class="form-group"><label asp-for="DefaultVisitProductHeaderName" class="control-label"></label><input asp-for="DefaultVisitProductHeaderName" class="form-control" /><span asp-validation-for="DefaultVisitProductHeaderName" class="text-danger"></span></div><br /><h4>Package Details</h4><hr /><div id="divPackageDetails" class="container">
                @Html.RenderAction("GetPackageDetails", "Package", new { id = string.Empty })</div><div class="text-right">                <button type="button" id="btn" class="btn btn-info" onclick="test()">Test</button>
                @Html.ActionLink("Back", "Index", "Package")</div></form></div></div>

@section Scripts{   
    <script>
        function test() {
            var lstPackageDetails = '@MyProject.Doctor.Controllers.PackageController.GetPackageDetailsForJS(this.Context)';
        }</script>
}

And here is my csharp method (GetPackageDetailsForJS) :

public static string GetPackageDetailsForJS(HttpContext context)
        {
            string strResult = string.Empty;

            strResult = HelperMethods.GetJsonStringFromTempData(context, "_lstPackageDetails");

            return strResult;
        }

My problem is that the test() event handles for button (btn) call my csharp method (GetPackageDetailsForJS) when page being loaded at the first time & can not call it when i click on button. so in my browser devTools, i'm facing an empty variable as follow :

<script>
        function test() {
            var lstPackageDetails = '[]';
        }</script>

Can anybody help me where is the problem & how to solve it?

Thanks in advance