I am trying to figure out a way to make the dropdown list of Rooms depending on the dropdown list of departments in my view. I'm struggling to access the viewbag in javascript but I haven't found a way to access it. Any help is appreciated

My Controller ->

public ActionResult CreateActivity()
{
    ViewBag.Departments = departmentRepository.Collection;
    ViewBag.Rooms = roomRepository.Collection;
    return View();
}

My View ->

<div>
    <select asp-for="Department.DepartmentID" onchange="this.form.submit()">
        @foreach (Department d in ViewBag.Departments)
        {
            <option value="@d.DepartmentID">@d.DepartmentName</option>
        }
    </select>
</div>

<span asp-validation-for="Room.RoomName"></span>
<div>
    <select asp-for="Room.RoomID" >
        <option value="" disabled selected hidden>Vælg Lokale</option>
        @foreach (Room r in ViewBag.Rooms)
        {
            <option value="@r.RoomID">@r.RoomName</option>
        }
    </select>
</div>

Room Model ->

public class Room
{
    public int RoomID { get; set; }
    [Required(ErrorMessage = "Lokalenavn mangler")]
    [MaxLength(40)]
    public string RoomName { get; set; }
    [Required(ErrorMessage = "Afdelingsnavn mangler")]
    public Department Department { get; set; }
}

Department Model ->

public class Department
{ 
    public int DepartmentID { get; set; }
    [Required(ErrorMessage = "Afdelingsnavn mangler")]
    [MaxLength(40)]
    public string DepartmentName { get; set; }
}

I have tried to access the viewbag with javascript but I haven't been able to do it. Any help is appreciated

CodePudding user response：

inside CreateActivity actionresult, you can set the values of ViewBag.Departments and ViewBag.Rooms into JSON or delimited string (convert the collection to a JSON or delimited string). Then assign the ViewBag.Departments and ViewBag.Rooms to a hidden input type elements in your view. Use javascript to access the values from hidden input type elements. not a good solution but you can see other options from there.