error - if list is zero checking in View, MVC.

Hello everyone,

I'm working on MVC 5, there is a viewmodel class and contain a static list as the same class.

public class PartnerProjectVM
{
public int idPartnerProject { get; set; }
public string ProjectName { get; set; }
public string ProjectDescription { get; set; }
public static List listPartnerProjectVM = new List();
}

In view,

How can I check

@model Reboxwebapp.Models.ViewModel.PartnerProjectVM
@if (listPartnerProjectVM.Count() != null)
{
<div class="col-sm-3">
<div>
<a class="list-group-item active left-menu-head">Projects Lista>
@foreach (var item in listPartnerProjectVM)
{
<a href="#" id="idProject" class="list-group-item" name="@item.idPartnerProject">@item.ProjectNamea>
}
div>
div>
}

Here error occurred. please help me...

@Catcher Wong, Sir I have changed the code like:-

Viewmodel,

public class PartnerProjectVM
{
public int idPartnerProject { get; set; }
public string ProjectName { get; set; }
public string ProjectDescription { get; set; }
public virtual List listPartnerProjectVM { get; set; }
}

Get/Post Method,

[HttpPost]
public ActionResult PremiumUserRegProjects(PartnerProjectVM partnerProjectVM
{
partnerProjectVM.listPartnerProjectVM = new List();
partnerProjectVM.listPartnerProjectVM.Add(partnerProjectVM);
return RedirectToAction("PremiumUserRegProjects");
}
[HttpGet]
public ActionResult PremiumUserRegProjects()
{
PartnerProjectVM partnerProjectVM = new PartnerProjectVM();
if (partnerProjectVM.listPartnerProjectVM != null && partnerProjectVM.listPartnerProjectVM.Count() > 0)
{
var lastItemProject = partnerProjectVM.listPartnerProjectVM.LastOrDefault();
partnerProjectVM.ProjectName = lastItemProject.ProjectName;
partnerProjectVM.ProjectDescription = lastItemProject.ProjectDescription;
return View("PremiumUserRegProjects", partnerProjectVM);
}
}

Issue occurred, the problem is filled list is now empty. please help me sir...

I did write:- PartnerProjectVM partnerProjectVM = new PartnerProjectVM();

with out using this new key word how can I access my list? mean, 'partnerProjectVM.listPartnerProjectVM' like this

Why you use the static list?

And you can try to use the following code

public class PartnerProjectVM
{
public int idPartnerProject { get; set; }
public string ProjectName { get; set; }
public string ProjectDescription { get; set; }
public virtual List ListPartnerProjectVM {get;set;}
}

and the view

@model Reboxwebapp.Models.ViewModel.PartnerProjectVM
@if (Model.ListPartnerProjectVM!=null && Model.ListPartnerProjectVM.Count > 0)
{
class="col-sm-3">
class="list-group-item active left-menu-head">Projects List
@foreach (var item in Model.ListPartnerProjectVM)
{
"#" id="idProject" class="list-group-item" name="@item.idPartnerProject">@item.ProjectName
}

6 Replies

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Abhilash J A9y ago
@Catcher Wong, Sir I have changed the code like:-

Viewmodel,
public class PartnerProjectVM
   {
       public int idPartnerProject { get; set; }
       public string ProjectName { get; set; }
       public string ProjectDescription { get; set; }
      public virtual List listPartnerProjectVM { get; set; }
   }
Get/Post Method,
[HttpPost]
        public ActionResult PremiumUserRegProjects(PartnerProjectVM partnerProjectVM
        {
             partnerProjectVM.listPartnerProjectVM = new List();
                partnerProjectVM.listPartnerProjectVM.Add(partnerProjectVM);
                return RedirectToAction("PremiumUserRegProjects");
        }

         [HttpGet]
        public ActionResult PremiumUserRegProjects()
        {
             PartnerProjectVM partnerProjectVM = new PartnerProjectVM();
             if (partnerProjectVM.listPartnerProjectVM != null && partnerProjectVM.listPartnerProjectVM.Count() > 0)
            {
              var lastItemProject = partnerProjectVM.listPartnerProjectVM.LastOrDefault();

                partnerProjectVM.ProjectName = lastItemProject.ProjectName;
                partnerProjectVM.ProjectDescription = lastItemProject.ProjectDescription;


                return View("PremiumUserRegProjects", partnerProjectVM);
            }
        }
Issue occurred, the problem is filled list is now empty. please help me sir...
I did write:- PartnerProjectVM partnerProjectVM = new PartnerProjectVM();

with out using this new key word how can I access my list? mean, 'partnerProjectVM.listPartnerProjectVM' like this
Catcher Wong9y ago
No , the keyword virtual can do that!!

As for me , I will make a new query to find out the data I need to show.
Abhilash J A9y ago
@Catcher Wong, sir thank you thank you for reply me. Actualy I am using static class for, I want to add all model object item to list and after insert whole items to db. With respect to your code, can I use Virtual keywork instead of static ?
Catcher Wong9y ago
Why you use the static list?

And you can try to use the following code
public class PartnerProjectVM
{
        public int idPartnerProject { get; set; }
        public string ProjectName { get; set; }
        public string ProjectDescription { get; set; }
        public virtual List ListPartnerProjectVM {get;set;}
}
and the view
@model Reboxwebapp.Models.ViewModel.PartnerProjectVM
@if (Model.ListPartnerProjectVM!=null && Model.ListPartnerProjectVM.Count > 0)
{
    class="col-sm-3">


            class="list-group-item active left-menu-head">Projects List
            @foreach (var item in Model.ListPartnerProjectVM)
            {
                "#" id="idProject" class="list-group-item" name="@item.idPartnerProject">@item.ProjectName
            }