Asp.net core 6 model databinding with dictionary - dictionary

Question

I have:
a) a list of days with timeslots:
timeslots
b) a list of locations:
locations
c) a link table that connects the locations with timeslots and where the users will populate the persons required in that timeslot and in that location:
Link table
I need to display a list of days with a checkbox for each timeslot in order to ask how many persons will be required in that location/timeslot (if any).
Now this is what i've done so far:
public class VolunteeringSlotViewModel
{
public VolunteeringSlotViewModel()
{
TimeSlots = new();
}
public DateOnly Date { get; set; }
public List<SelectListItem> TimeSlots { get; set; }
}
in the viewmodel:
public List<VolunteeringSlotViewModel> TimeSlots { get; set; } //lists all timeslots
public List<int> SelectedTimeSlots { get; set; } //will get selected checkboxes
public Dictionary<string,string> TimeSlotVolunteers { get; set; } // will host volunteers number required to the related (selected checkbox) time slot
In the view:
<h5>Time slots</h5>
#foreach (var v in Model.TimeSlots)
{
<div class="ml-2">
<p class="mb-n1"><u><strong>#v.Date.ToShortDateString()</strong></u></p>
#foreach (var t in v.TimeSlots)
{
<div class="form-group form-check ml-5 d-inline-flex align-items-center mb-1 ">
<input class="form-check-input" name="SelectedTimeSlots" type="checkbox"
value="#t.Value"
id="checkbox_v_#t.Value"
checked="#t.Selected" />
<label class="form-check-label mr-2" for="checkbox_t_#t.Value">#t.Text </label>
<input type="hidden" name="TimeSlotVolunteers[#t.Value].Key" value="#t.Value" />
<input class="form-control w-25" style="-moz-appearance: textfield;" type="number" name="TimeSlotVolunteers[#t.Value].Value" id="TimeSlotVolunteers[#t.Value]" value="#Model.TimeSlotVolunteers[t.Value]" />
</div>
}
</div>
}
Now the form appears like this:
rendered view
The checkboxes are working correctly but dictionary, where i want to set the [Value] with the number written in the textboxes, just populates the [key] field: the [Values] are always null.
I got it working in a dirty way, adding these lines in the controller's action but this was just to understand if data was written inside the form in some way.
for (int i = 1; i < 19; i++)
{
string key= "TimeSlotVolunteers[" + i.ToString()+"].Value";
vm.TimeSlotVolunteers[i.ToString()] = Request.Form[key];
}
I would like to make the databinding work and i thought it was related to the names of the controls but i cant figure out how to fix it.
Can you please help?
Thanks
I tried to use various textboxes code like
<input asp-for="TimeSlotVolunteers[#t.Value].Value" type="text" class="form-control" />
Adding and removing the ID= but the Dictionary values are always null.
At this point i'm wondering if this databinding is supported out of the box or a custom data binder is required