Why DefaultModelBinder doesn't bind route value ID from URL - asp.net-mvc

Question

ASP.NET MVC
In short:
I have a get action and a post action
when I type in browser localhost:port/Employee/Edit/1 I call get action, so in URL I have this whole url string. When I press submit button, in post action defaultmodelbinder doesnt bind id from URL!!!! I HAVE TO ADD HIDDEN FIELD for id. But why? I also have delete action (post), that gets id too, and I dont need to add hidden field for id. why?
More specifically:
I have the model:
public class EmployeeViewModel
{
public Int32 EmployeeId { get; set; }
public String Name { get; set; }
public String Phone { get; set; }
public String Email { get; set; }
public String Other { get; set; }
}
And 2 actions
public ActionResult Edit(int id)
{
try
{
EmployeeViewModel model;
using (var dbSession = NHibernateHelper.OpenSession())
{
var employee = dbSession.Query<Employee>().First(e => e.EmployeeId == id && e.ExpireDate==null);
model = new EmployeeViewModel(employee);
}
return View(model);
}
catch
{
return View("Error");
}
}
[HttpPost]
public ActionResult Edit(EmployeeViewModel model)
{
try
{
using (var dbSession=NHibernateHelper.OpenSession())
using (var transaction=dbSession.BeginTransaction())
{
var employee = model.ToEmployee();
dbSession.Merge(employee);
transaction.Commit();
}
return RedirectToAction("Index");
}
catch
{
return View("Error");
}
}
And 1 View (HERE I HAVE TO WRITE THIS LINE #Html.HiddenFor(model => model.EmployeeId) )
#using (Html.BeginForm()){
#Html.AntiForgeryToken()
<div class="form-horizontal">
<hr />
#Html.ValidationSummary(true, "", new { #class = "text-danger" })
<div class="form-group">
#Html.HiddenFor(model => model.EmployeeId)
#Html.LabelFor(model => model.Name, htmlAttributes: new {#class = "control-label col-md-2"})
<div class="col-md-10">
#Html.EditorFor(model => model.Name, new {htmlAttributes = new {#class = "form-control"}})
#Html.ValidationMessageFor(model => model.Name, "", new {#class = "text-danger"})
</div>
</div>
<div class="form-group">
#Html.LabelFor(model => model.Phone, htmlAttributes: new { #class = "control-label col-md-2" })
<div class="col-md-10">
#Html.EditorFor(model => model.Phone, new { htmlAttributes = new { #class = "form-control" } })
#Html.ValidationMessageFor(model => model.Phone, "", new { #class = "text-danger" })
</div>
</div>
<div class="form-group">
#Html.LabelFor(model => model.Email, htmlAttributes: new { #class = "control-label col-md-2" })
<div class="col-md-10">
#Html.EditorFor(model => model.Email, new { htmlAttributes = new { #class = "form-control" } })
#Html.ValidationMessageFor(model => model.Email, "", new { #class = "text-danger" })
</div>
</div>
<div class="form-group">
#Html.LabelFor(model => model.Other, htmlAttributes: new { #class = "control-label col-md-2" })
<div class="col-md-10">
#Html.EditorFor(model => model.Other, new { htmlAttributes = new { #class = "form-control" } })
#Html.ValidationMessageFor(model => model.Other, "", new { #class = "text-danger" })
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Сохранить" class="btn btn-default" />
</div>
</div>
</div>}

Answer 1

Because the parameter in the method is named id and the property in
your model is named EmployeeId They are not the same. And if you
change the model property to Id it will be bound
Thanks, Stephen Muecke