'Newtonsoft.Json.JsonSerializationException' occurred in Newtonsoft.Json.dll but was not handled in user code

Question

I need to store my IEnumerable of objects into Tempdata for my next request from the server. Since Tempdata cannot store Objects I found the below extenstion method to serialize and deserialize before putting into Tempdata. After this method, I am able to store my object to Tempdata. But, when I am trying to use it in my next action method, I am facing following runtime error. "Cannot deserialize the current JSON array". Please help me to fix this issue.

my code :

public ActionResult GetData(){
List<EmployeeViewModel> webform = 
_service.GetListOfWebformData(id).ToList();
TempData.Put("webform", webform); }

public ActionResult ShowData(){
var WebformData = TempData.Get<EmployeeViewModel>("webform");
return View(WebformData);}

Extension method i have used for Tempdata is below

public static class TempDataExtensions
{
    public static void Put<T>(this ITempDataDictionary tempData, string key, T value) where T : class
    {
        tempData[key] = JsonConvert.SerializeObject(value);
    }

    public static T Get<T>(this ITempDataDictionary tempData, string key) where T : class
    {
        object o;
        tempData.TryGetValue(key, out o);
        return o == null ? null : JsonConvert.DeserializeObject<T>((string)o);
    }
}