How to use checkboxes for batch operation? - asp.net-mvc-5

Question

Say I have a view like this:
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#assign">
Assign
</button>
<table class="table table-hover table-bordered table-sm">
<thead class="thead-light">
<tr>
<th></th>
<th>Name</th>
</tr>
</thead>
#foreach (var employee in ViewBag.employees)
{
<tr>
<td><input type="checkbox" name="#employee.Id" /></td>
<td>#employee.Name</td>
</tr>
}
</table>
<!-- Modal -->
<div class="modal fade" id="assign" tabindex="-1" role="dialog">
<div class="modal-dialog modal-dialog-centered" role="document">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="modalTitle">Assign employee to group</h5>
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div class="modal-body">
<!-- a dropdown of groups -->
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-dismiss="modal">Cancel</button>
<button type="button" class="btn btn-primary">Assign</button>
</div>
</div>
</div>
</div>
And I have a controller to call:
public ActionResult Assign(List<int> employeeIds, int groupId)
How can I get the list of Ids that are checked and the groupId from the dropdown in modal, so that I can call the controller?
For example if the data look like this
0. Alice
1. Bob
2. Charlie
3. Dan
And I checked Bob and Charlie and want to assign them to group 1, so the employeeIds will be 1 and 2, and groupId will be 1.

Answer 1

You need to use for loop instead of foreach. Besides, I suggest to use ViewModel instead of ViewBag.
#using (Html.BeginForm("Index", "Home", FormMethod.Post, null))
{
for (int i = 0; i < Model.Employees.Count; i++)
{
<tr>
<td>#Html.CheckBoxFor(x => Model.Employees[i].Checked)</td>
<td>#Model.Employees[i].Name</td>
</tr>
}
<input type="submit" value="Submit" />
}
Model
You want to rename ViewModel something meaningful.
public class ViewModel
{
public List<Employee> Employees { get; set; }
public int GroupId { get; set; }
}
public class Employee
{
public int Id { get; set; }
public string Name { get; set; }
public bool Checked { get; set; }
}
Controller
public class HomeController : Controller
{
public ActionResult Index()
{
ViewModel vm = new ViewModel
{
Employees = new List<Employee>
{
new Employee {Id=1, Name = "John", Checked = true},
new Employee {Id=2, Name = "Eric", Checked = false}
}
};
return View(vm);
}
[HttpPost]
public ActionResult Index(ViewModel vm)
{
return View(vm);
}
}
Here is another way.