how i can send multivalue to create action - asp.net-mvc

Question

i have a doctor i want add doctor subspecialty to the doctor from sub specialties table many to many relationship
i need to add subspecialties from multiselect list but my controller only add first selection , i want my create controller take all passed subspecialties and create it
my model
public partial class DoctorSubSpecialty
{
public int Id { get; set; }
public Nullable<int> DoctorId { get; set; }
public Nullable<int> SubSpecialtyId { get; set; }
public virtual DoctorProfile DoctorProfile { get; set; }
public virtual SubSpecialty SubSpecialty { get; set; }
}
}
create get action
public ActionResult Create()
{
ViewBag.DoctorId = new SelectList(db.DoctorProfiles, "Id", "FullName");
ViewBag.SubSpecialtyId = new MultiSelectList(db.SubSpecialties, "id", "Name");
return View();
}
create post action
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Create([Bind(Include = "Id,DoctorId,SubSpecialtyId")] DoctorSubSpecialty doctorSubSpecialty)
{
DoctorSubSpecialty doctorSub = db.DoctorSubSpecialties.Where(d => d.DoctorId == doctorSubSpecialty.DoctorId & d.SubSpecialtyId == doctorSubSpecialty.SubSpecialtyId).FirstOrDefault();
if (doctorSub == null) {
db.DoctorSubSpecialties.Add(doctorSubSpecialty);
await db.SaveChangesAsync();
}
my view
#using (Html.BeginForm())
{
#Html.AntiForgeryToken()
<div class="form-horizontal">
<h4>DoctorSubSpecialty</h4>
<hr />
#Html.ValidationSummary(true, "", new { #class = "text-danger" })
<div class="form-group">
#Html.LabelFor(model => model.DoctorId, "DoctorId", htmlAttributes: new { #class = "control-label col-md-2", #id = "DoctorID" })
<div class="col-md-10">
#Html.DropDownList("DoctorId", null, htmlAttributes: new { #class = "form-control" })
#Html.ValidationMessageFor(model => model.DoctorId, "", new { #class = "text-danger" })
</div>
</div>
<div class="form-group">
#Html.LabelFor(model => model.SubSpecialtyId, "SubSpecialtyId", htmlAttributes: new { #class = "control-label col-md-2" })
<div class="col-md-10">
#Html.DropDownList("SubSpecialtyId",(MultiSelectList)ViewBag.SubSpecialtyId, htmlAttributes: new { #multiple = "multiple", #class = "form-control" })
#Html.ValidationMessageFor(model => model.SubSpecialtyId, "", new { #class = "text-danger" })
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Create" class="btn btn-default" />
</div>
</div>
</div>
}

Answer 1

Create a ViewModel specific to your usecase that can actually transport more than one Id.
I.e. you will need an int[] to bind the selection to.
A ViewModel also helps you to get rid of all this ViewBag and [Bind] nonsense.
public class CreateDoctorSubSpecialtyViewModel {
// These are the selected values to be posted back
public int DoctorId { get; set; }
public int[] SubSpecialtyIds { get; set; }
// These are the possible values for the dropdowns
public IEnumerable<SelectListItem> DoctorProfiles { get; set; }
public IEnumerable<SelectListItem> SubSpecialties { get; set; }
}
GET action - initialize the ViewModel and pass it to the View:
[HttpGet]
public ActionResult Create() {
var doctorProfiles = db.DoctorProfiles.Select(d =>
new SelectListItem {
Text = d.FullName,
Value = d.Id
}
).ToArray();
var subSpecialties = db.SubSpecialties.Select(s =>
new SelectListItem {
Text = s.Name,
Value = s.id
}
).ToArray();
var viewModel = new CreateDoctorSubSpecialtyViewModel {
DoctorProfiles = doctorProfiles,
SubSpecialties = subSpecialties
};
return View("Create", viewModel);
}
View "Create.cshtml" (styling removed for clarity) - tell MVC which ViewModel we want to use with #model:
#model CreateDoctorSubSpecialtyViewModel
#using (Html.BeginForm("Create", "YourControllerName", FormMethod.Post)) {
#Html.DropDownListFor(m => m.DoctorId, Model.DoctorProfiles)
#Html.DropDownListFor(m => m.SubSpecialtyIds, Model.SubSpecialties, new { multiple = "multiple" })
<input type="submit" />
}
POST action - use Linq Contains to test against multiple submitted SubSpecialtyIds:
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Create(CreateDoctorSubSpecialtyViewModel postData) {
DoctorSubSpecialty[] allSelectedSubSpecialities = db.DoctorSubSpecialties
.Where(d => d.DoctorId == postData.DoctorId
&& postData.SubSpecialtyIds.Contains(d.SubSpecialtyId))
.ToArray();
// ...
}
EDIT #Html.DropDownListFor requires an IEnumerable<SelectListItem> as second parameter.