Pass List of Checkboxes into View

Question

User490317677 posted

I have a list of items that will be associated to a user. It's a one-to-many relationship. I want the entire list of items passed into the view so that they can choose from ones that are not associated to them yet (and also see those that are already associated). I want to create checkboxes from these. I then want to send the selected ones back into the controller to be associated. How can I pass in the list of all of them, including those that aren't yet associated, and reliably pass them back in to be associated?

ViewModel:

public class RightsVM
{
    public int ID { get; set; }
    public string Name { get; set; }
    public bool IsSelected { get; set; }
}

public class UserVM
{
    public UserVM()
    {
        Rights = new List<RightsVM>();
    }
    public int ID { get; set; }
    public string Name { get; set; }
    public List<RightsVM> Rights{ get; set; }
}

In the GET method, i get Problem/Error when i try to assigned property for Roles: Cannot Convert string to Generic List:

Given rights.RightsCode (Is property which is coming from Database) is a string, how can i expecting that string  become a List<RightsVM>

public ActionResult UserEdit(int IDs)
{
    UserVM model = new UserVM();

    var query = (from px in db.PX2
                 join rights in db.Rights on px.Email_ID equals rights.Mail
                 where px.Id == IDs
                 select new UserVM
                  {
                     Rights = rights.RightsCode, **//Cannot Convert String to List**
                     ID = rights.Id,
                  });


   return View(model);
}

View:

 @using (Html.BeginForm())
 {
    @Html.HiddenFor(m => m.ID)
    @Html.DisplayFor(m => m.Name)
    for (int i = 0; i < Model.Roles.Count; i++)
     {
        @Html.HiddenFor(m => m.Roles[i].ID)
        @Html.CheckBoxFor(m => m.Roles[i].IsSelected)
        @Html.LabelFor(m => m.Roles[i].IsSelected, Model.Roles[i].Name)
      }
      <input type"submit" />
   }

Answer 1

User475983607 posted

The MVC Getting Started tutorials covers this specific pattern; https://docs.microsoft.com/en-us/aspnet/mvc/overview/getting-started/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-application

I recommend starting for the begging of the tutorial though.

https://docs.microsoft.com/en-us/aspnet/mvc/overview/getting-started/getting-started-with-ef-using-mvc/

Answer 2

User-474980206 posted

this query:

    var query = (from px in db.PX2
                 join rights in db.Rights on px.Email_ID equals rights.Mail
                 where px.Id == IDs
                 select new UserVM
                  {
                     Rights = rights.RightsCode, **//Cannot Convert String to List**
                     ID = rights.Id,
                  });

returns a row for every Rights row. you use the group by to group the rows by Id.

var query = (from px in db.PX2
   join rights in db.Rights on px.Email_ID equals rights.Mail
   where px.Id == IDs
   group new {px, rights} by new {px.Id} into g
   select new UserVM
   {
       Rights = g.Rights.Select(r => new RightsVM 
       {
          r.Id, 
          r.Name, 
          r.IsSelected
       }).ToList()
       ID = g.px.Id,
   }).ToList();

Answer 3

User490317677 posted

No Luck Bruce :( get serveral errors.

Answer 4

User-2054057000 posted

Your question is based entirely on the Model Binding concept. I found that a similar question has been answered here, please check it and let me know if it is useful.

Answer 5

User-17257777 posted

Hi ManDown,

The type of “Rights” in UserVM is List<RightsVM> and the type of “RightsCode” is String, String cannot convert to List, so you have this error. Assuming that you store the rights in the RightsCode and are separated by "," you can first convert the RightsCode to an array using the split(',') method like this:

string RightsCode = "r1,r2,r3,r4,r5";
string[] RightsArray= RightsCode.Split(',');

Then convert the resulting array into a List<RightsVM>. If the actual situation is different from what I guess, I hope that you can provide us with the specific code of the “PX2” and “Rights” entities.

Best Regards,

Jiadong Meng.