added null check on view shifts

Project.Zap/Views/Shift/ViewShifts.cshtml

@@ -11,12 +11,15 @@
 <h1>@Localizer["Title"]</h1>
 
 
-@if (ViewData.ContainsKey("NoShifts"))
+@if(ViewData.ContainsKey("NoShifts"))
 {
 <div class="alert alert-info">
     <strong>@Localizer["ErrorTitle"]</strong> @ViewData["NoShifts"]
-</div>}
+</div>
+}
 
+@if(Model != null && Model.Any())
+{
 <div class="container">
     <div class="row">
         <div class="d-none d-xs-block d-sm-block col-md-4 font-weight-bold">@Localizer["TableStoreName"]</div>
@@ -37,7 +40,9 @@
     <div class="col-xs-6 col-sm-6 col-md-2">@shift.WorkType</div>
 
     <a class="btn btn-danger col-xs-6 col-sm-6 col-md-2" asp-controller="Shift" asp-action="CancelShift" asp-route-StoreName="@shift.StoreName" asp-route-Start="@shift.Start.ToString("yyyy-MM-ddTHH:mm")" asp-route-End="@shift.End.ToString("yyyy-MM-ddTHH:mm")" asp-route-WorkType="@shift.WorkType">@Localizer["CancelButton"]</a>
-    
-</div>
-    }
+
+</div>}
 </div>
+
+}
+