After Submit TotalPages Throws error - ajax

Question

I have a little problem with my paging ("double TotalPage = #ViewBag.TotalPages; on Partial View"), after submiting on Create or Edit the paging throws the following error: "Cannot convert null to 'double' because it is a non-nullable value type". I have created a partial view that contains the list (Crud Operations using Ajax), all works fine, I can go to different pages in the list but when I submit a new row or edit an existing one it displays that error. Here is the code for it:
public ActionResult IndexApp(string Page)
{
var appc = objBs.appointmentdiaryBs.GetALL();
appc = from ac in db.tbl_Appoiment_Diary
select ac;
ViewBag.TotalPages = Math.Ceiling(objBs.appointmentdiaryBs.GetALL().Count() / 5.0);
int page = int.Parse(Page == null ? "1" : Page);
ViewBag.Page = page;
appc = appc.Skip((page - 1) * 5).Take(5);
ViewBag.Count = db.tbl_Appoiment_Diary.SqlQuery("SELECT * FROM dbo.tbl_Appoiment_Diary").Count();
return View(appc.ToList());
}
here is the partial view:
#model IEnumerable<BOL3.tbl_Appoiment_Diary>
<div class="table-responsive">
<table class="table" id="tbl" style="border-collapse: separate; border: solid grey 1px; border-radius: 6px; -moz-border-radius: 6px;">
<thead>
<tr style="background-color:aqua">
<th>
#Html.ActionLink("Title", "Title", "IndexApp", new { SortOrder = ViewBag.SortOrder == null ? "Asc" : (ViewBag.SortOrder == "Asc" ? "Des" : "Asc"), SortBy = "Title", page = (ViewBag.Page == null ? "1" : ViewBag.Page) })
</th>
<th>
#Html.ActionLink("Scheduled Date and Time", "DateTimeScheduled", "IndexApp", new { SortOrder = ViewBag.SortOrder == null ? "Asc" : (ViewBag.SortOrder == "Asc" ? "Des" : "Asc"), SortBy = "DateTimeScheduled", page = (ViewBag.Page == null ? "1" : ViewBag.Page) })
</th>
<th>
#Html.ActionLink("Appointment Lenght", "AppointmentLenght", "IndexApp", new { SortOrder = ViewBag.SortOrder == null ? "Asc" : (ViewBag.SortOrder == "Asc" ? "Des" : "Asc"), SortBy = "AppointmentLenght", page = (ViewBag.Page == null ? "1" : ViewBag.Page) })
</th>
<th></th>
</tr>
</thead>
<tbody>
#foreach (var item in Model)
{
<tr>
<td>
#Html.DisplayFor(modelItem => item.Title)
</td>
<td>
#Html.DisplayFor(modelItem => item.DateTimeScheduled)
</td>
<td>
#Html.DisplayFor(modelItem => item.AppointmentLenght)
</td>
<td style="align-content:center">
Edit |
#Html.ActionLink("Delete", "Delete", new { id = item.ID })
</td>
</tr>
}
</tbody>
</table>
#{
double TotalPage = #ViewBag.TotalPages;
}
<ul class="pagination pagination-sm">
#for (int i = 1; i <= TotalPage; i++)
{
if (i == ViewBag.Page)
{
<li class="active">#Html.ActionLink(i.ToString() + " ", "IndexApp", new { SortOrder = (ViewBag.SortOrder == null ? "Asc" : ViewBag.SortOrder), SortBy = (ViewBag.SortBy == null ? "Title" : ViewBag.SortBy), Page = i })</li>
}
else
{
<li>#Html.ActionLink(i.ToString() + " ", "IndexApp", new { SortOrder = (ViewBag.SortOrder == null ? "Asc" : ViewBag.SortOrder), SortBy = (ViewBag.SortBy == null ? "Title" : ViewBag.SortBy), Page = i })</li>
}
}
</ul>
</div>
and here is the Index view:
<div id="main-div">
<div class="clearfix"> </div>
<div class="clearfix"> </div>
<div class="container">
Adauga
<br />
<div id="div-record1">
#Html.Partial("_Detail")
</div>
</div>
</div>