Develop Reference

Binding DropdownList property to controller method in ASP.NET Core

I'm trying to get a dropdown working on the create view for a particular model object. In this case, the model in question is Department, and within that object, there is another model object referenced called Division.
My Department model is a fairly basic POCO except for the property called Division which references another POCO (which, mind you, has simply an Id field and a Name field for the most part).
I already have a working dropdown for the create view (see code below)
<div class="form-group">
<label asp-for="Division" class="control-label"></label>
#Html.DropDownListFor(dept => dept.Division, new SelectList(ViewBag.Divisions, "Id", "Name"))
</div>
Yes, in the Create method that returns the view I'm populating the ViewBag.Divisions list and that's all working as planned.
However, in the Create method of my controller, while it's binding to the other (text) fields on the view I cannot figure out how to get it to populate the Division property for the Department object with the selection from the drop-down. My create method is below:
public async Task<IActionResult> Create([Bind("Id,Name,Description,IsActive,Division")] Department department)
{
if (ModelState.IsValid)
{
_context.Add(department);
await _context.SaveChangesAsync();
return RedirectToAction(nameof(Index));
}
return View(department);
}
Also, here are my model classes:
public class Division
{
[Key]
public int Id { get; set; }
[Required]
[Display(Name = "Division Name")]
public string Name { get; set; }
[Display(Name = "Active")]
public bool IsActive { get; set; }
}
public class Department
{
[Key]
public int Id { get; set; }
[Required]
[Display(Name = "Department Name")]
public string Name { get; set; }
public string Description { get; set; }
public Division Division { get; set; }
[Display(Name = "Active")]
public bool IsActive { get; set; }
}
The idea being that a particular department belongs to (and is associated with) a single division.
Thanks!

Write your Department class as follows:
public class Department
{
[Key]
public int Id { get; set; }
[ForeignKey("Division")]
public int DivisionId {get; set;}
[Required]
[Display(Name = "Department Name")]
public string Name { get; set; }
public string Description { get; set; }
[Display(Name = "Active")]
public bool IsActive { get; set; }
public Division Division { get; set; }
}
Then in the controller method:
public async Task<IActionResult> Create([Bind("Id,Name,Description,IsActive,DivisionId")] Department department)
{
if (ModelState.IsValid)
{
_context.Add(department);
await _context.SaveChangesAsync();
return RedirectToAction(nameof(Index));
}
return View(department);
}
Then in the View:
<div class="form-group">
<label asp-for="Division" class="control-label"></label>
#Html.DropDownListFor(dept => dept.DivisionId, new SelectList(ViewBag.Divisions, "Id", "Name"))
</div>

Here is a simple demo , you could try it
Add a ViewModel with a IList as the property for your dropdownlist items.
public class DepartmentViewModel
{
public int Id { get; set; }
public string Name { get; set; }
public IList<int> Divisions { get; set; }
}
The code in Create.cshtml
#model BindDropDownList.Models.DepartmentViewModel
<div class="form-group">
<label asp-for="#Model.Divisions" class="control-label"></label>
#Html.DropDownListFor(depart=>depart.Divisions , (List<SelectListItem>)ViewBag.Divisions)
</div>
In Controller,retrieve ViewBag.Divisions
ViewBag.Divisions = _context.Division.Select(d => new SelectListItem { Value=d.Id.ToString(),Text=d.Name}).ToList();
Change the Create method like below
public async Task<IActionResult> Create(DepartmentViewModel department)
{
//Add department
}

Pass model from a view to a controller (MVC)

When passing the model from my view to my controller, the data is all null. I was able to successfully pass it using an ActionLink but I don't think that is the best way; for security reasons (I do not want sensitive data in the querystring).
My models
public class DashboardModel
{
// Dasboard quick numbers
public int TotalUsers { get; set; }
public int TotalUnauthUsers { get; set; }
public int GamesPlayed { get; set; }
public int AssociatedGroups { get; set; }
public int TotalGroups { get; set; }
// Dashboard table
public IEnumerable<ManageUserData> UnauthUsers { get; set; }
}
public class ManageUserData
{
public string UserName { get; set; }
public int AlternateId { get; set; }
public string Email { get; set; }
public string Role { get; set; }
public IEnumerable<string> InvestigatorGroups { get; set; }
public string Institution { get; set; }
// User status
public bool AccountLocked { get; set; }
public bool EmailConfirmed { get; set; }
}
Snippet of my view
#model TestGame.ViewModels.DashboardModel
#foreach (var user in Model.UnauthUsers)
{
<tr>
<td>#user.UserName</td>
<td>#user.AlternateId</td>
<td>#user.Email</td>
<td>#user.Role</td>
<td>
#if (!user.EmailConfirmed)
{
<div class="text-warning">Unconfirmed Email</div>
}
#if (user.AccountLocked)
{
<div class="text-danger">Account Locked</div>
}
</td>
<td>
#if (user.AccountLocked || !user.EmailConfirmed)
{
using (Html.BeginForm("Manage", "Admin", FormMethod.Post))
{
#Html.HiddenFor(x => user.UserName)
#Html.HiddenFor(x => user.Email)
<input type="submit" value="Manage" />

You have to make sure the path starts with the object being posted back; what you have will work great if the action being posted to (HttpPost Admin/Manage action) takes an object of type User; if it takes an object of the model type, change your form to the following:
for (var i = 0; i < Model.UnAuthUsers.Count; i++)
using (Html.BeginForm("Manage", "Admin", FormMethod.Post))
{
#Html.HiddenFor(x => x.UnAuthUsers[i].UserName)
#Html.HiddenFor(x => x.UnAuthUsers[i].Email)
<input type="submit" value="Manage" />
Creating a reference from the model (being x) will do the trick.
EDIT: Based on comments, add two properties to your model:
public class DashboardModel
{
public string SelectedUserName { get; set; }
public string SelectedEmail { get; set; }
}
In your form, render a hidden for for that name; I've had trouble using HiddenFor, so I've in the past used the hidden directly:
using (Html.BeginForm("Manage", "Admin", FormMethod.Post))
{
<input type="hidden" name="#Html.NameFor(i => i.SelectedUserName)" value="#Model.UnauthUsers[i].UserName" />
<input type="hidden" name="#Html.NameFor(i => i.SelectedEmail)" .. />
And upon submitting the form, the user from that form will be posted back via the model, via these new properties.

How to post list of model on controller?

There is 1 form on which i will ask for Academic Details for :
Graduation
Post Graduation(Masters)
Professional Qualification.
So far any user say UserId="1" 3 entries will be created in my AcademicMaster each for bachelor,Master(Post Graduation) and Professional Qualification.
My Database AcademicMaster table fields and datamodel:
Id,Qualification(GraduationCourses),Acheievement,UserId
View Model:
public class AcademicViewModel
{
public int Id { get; set; }
public virtual Graduation Graduation{ get; set; }
public virtual PostGraduation PostGraduation{ get; set; }
public virtual ProfessionalQualification ProfessionalQualification{ get; set; }
}
public class Graduation
{
public string BachelorQualification { get; set; }
public string BachelorAchievement { get; set; }
}
public class PostGraduation
{
public string MasterQualification { get; set; }
public string MasterAchievement { get; set; }
}
public class ProfessionalQualification
{
public string ProfessionalQualifications { get; set; }
}
So my View is like this:
#model AcademicViewModel
#{
IEnumerable<SelectListItem> graduationList = ViewBag.GraduationList;
IEnumerable<SelectListItem> postGraduationList = ViewBag.PostGraduationList;
}
#using (Html.BeginForm())
{
<div class="row">
Bachelors
#Html.DropDownListFor(model => model.Graduation.Qualification, graduationList)
</div>
#Html.TextAreaFor(model => model.Graduation.Achievement)
<div class="row">
MASTERS
#Html.DropDownListFor(model => model.PostGraduation.Qualification, postGraduationList)
</div>
#Html.TextAreaFor(model => model.PostGraduation.Achievement)
<div class="row">
PROFESSIONAL QUALIFITCATION
#Html.TextAreaFor(model => model.ProfessionalQualification.ProfessionalQualifications)
</div>
<input type="submit" value="Save">
}
This is my Controller:
[HttpPost]
public ActionResult MyController(AcademicViewModel model)
{
//Actions
}
So is my View Model structure appropriate and how to create 3 entries in AcademicMaster Table??

I will start by saying that having one table may not be the best choice (what happens if later you start adding additional properties which may be applicable to Graduation that are not applicable to Professional - for example YearOfGraduation - you could end up with a huge number of fields, many of which may have null values.
However, if you want one table, then at least add another field so that you can identify if the data is related to Graduation, PostGraduation or Professional. The associated data model for the AcademicMasters table would be
public class AcademicMaster
{
public int ID { get; set; }
public string Type { get; set; } // may be an enum?
public string Qualification { get; set; }
public string Achievement { get; set; }
public int UserID { get; set; }
}
Side note: It might be better to use an enum for the Type property
public enum AcademicType
{
Graduation,
PostGraduation,
Professional
}
There does not seem to be any need to your current Graduation, PostGraduation and ProfessionalQualification models and your view model should be
public class AcademicViewModel
{
public string GraduationQualification { get; set; }
public string GraduationAchievement { get; set; }
public string PostGraduationQualification { get; set; }
public string PostGraduationAchievement { get; set; }
public string ProfessionalAchievement { get; set; }
public IEnumerable<SelectListItem> GraduationList { get; set; }
public IEnumerable<SelectListItem> PostGraduationList { get; set; }
}
Side notes: Its not clear what your current ProfessionalQualifications property is - does that get assigned to the Qualification field or the Acheievement field in the database? Since your using a view model, then it should include the SelectList's rather that using ViewBag.
Then your view will be
#model AcademicViewModel
#using (Html.BeginForm())
{
<h2>Graduation</h2>
#Html.DropDownListFor(m => m.GraduationQualification, Model.GraduationList)
#Html.TextAreaFor(m => m.GraduationAchievement)
... // repeat for PostGraduation and Professional
<input type="submit" value="Save">
}
And the POST method would be
[HttpPost]
public ActionResult MyController(AcademicViewModel model) // should be named Create?
{
var userID = ....
AcademicMaster graduation = new AcademicMaster
{
Type = AcademicType.Graduation,
Qualification = model.GraduationAchievement,
Achievement = model.GraduationAchievement,
UserId = userID;
};
db.AcademicMasters.Add(graduation);
// Repeat for PostGraduation and Professional
db.SaveChanges();
// redirect?
}

MVC, Saving Data into 2 or more Related models from a single Form / View .?

My Model:
(i) For Transaction
public class Transaction
{
[Key]
public int TransactionId { get; set; }
public DateTime OnWardDate { get; set; }
public DateTime ReturnDate { get; set; }
public virtual UserProfile User { get; set; }
}
(ii) For User
public class UserProfile
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int UserId { get; set; }
public string UserName { get; set; }
private UserDetails _details = new UserDetails();
public virtual UserDetails details
{
get { return _details; }
}
}
(ii) For UserDetails
public class UserDetails
{
[Key]
public int DetailsId { get; set; }
public string DLNum { get; set; }
}
My Controller for Create Transaction:
// GET: /Transaction/Create
public ActionResult Create()
{
return View();
}
//
// POST: /Transaction/Create
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(Transaction transaction)
{
if (ModelState.IsValid)
{
db.Transactions.Add(transaction);
db.SaveChanges();
return RedirectToAction("Index");
}
return View(transaction);
}
My View for Create transaction:
<div class="editor-label">
#Html.LabelFor(model => model.OnWardDate)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.OnWardDate)
#Html.ValidationMessageFor(model => model.OnWardDate)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.User.details.DLNum)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.User.details.DLNum)
#Html.ValidationMessageFor(model => model.User.details.DLNum)
</div>
When I Submit the form... model.OnWardDate is getting saved but model.User.details.DLNum is not saving
I hv seen about ViewModel. Is that the only option to go with it?
Thanks In Advance.

In your case, I would think it's because your setter is private for UserDetails:
public virtual UserDetails details
{
get { return _details; }
}
If you're creating the tables based on those models and therefore can't afford to modify them, I would indeed advise to make a view model, post using that and then create / update the database entry accordingly.

The main issue is that Entity Framework requires both getter and setter for the POCO properties your class UserDetails only has a getter defined for the details property.
Your models could then be:
public class Transaction
{
[Key]
public int TransactionId { get; set; }
public DateTime OnWardDate { get; set; }
public DateTime ReturnDate { get; set; }
public virtual UserProfile User { get; set; }
}
public class UserProfile
{
[Key]
public int UserId { get; set; }
public string UserName { get; set; }
public virtual UserDetails Details { get; set; }
}
public class UserDetails
{
[Key]
public int DetailsId { get; set; }
public string DLNum { get; set; }
}
2. I recommend using the pattern of instantiating the model in the Controller and passing it to the view as in:
public ActionResult Create()
{
var transaction = new Transaction
{
User = new UserProfile
{
Details = new UserDetails()
}
};
return View(transaction);
}
This ensures your model is properly constructed and allows you to initialize any properties before the view is rendered. You can often get away shortcutting this, IMHO it is better to be explicit.

MVC3 Optional Model Property

I have a dropdownlist which I would like to be optional, however, the ModelState.IsValid check is trying to validate the property. Is there a way to tell it the property is optional?
Here is my code:
<h2>New Version</h2>
#using (Html.BeginForm()) {
<div>Version Number: #Html.TextBoxFor(m => m.Number)</div>
<div>Enabled: #Html.CheckBoxFor(m => m.IsActive)</div>
<div></div>
<div>
Template (optional):
#Html.DropDownListFor(m => m.TemplateVersionId, new SelectList(Model.CurrentVersions, "VersionId", "Number"),
"-- Select Template --")
</div>
<input type="submit" value="Save" />
#Html.ActionLink("Cancel", "Index");
}
and my ViewModel:
public class AddVersionViewModel
{
public double Number { get; set; }
public bool IsActive { get; set; }
public int TemplateVersionId { get; set; }
public ICollection<Version> CurrentVersions { get; set; }
}
I want the TemplateVersionId to be optional.

Change it to an int? to make it nullable.

When you create Nullable items it becomes optional in forms
public class AddVersionViewModel
{
public double Number { get; set; }
public bool IsActive { get; set; }
public int? TemplateVersionId { get; set; }
public ICollection<Version> CurrentVersions { get; set; }
}