How to "extend" model validation? - asp.net-mvc

Question

I have a two pages:
Create page that uses Data Annotations validation.
Edit page.
Both pages use different models. I have to use a specific model for the Edit page in order for the values of the selected row to display. How do I:
Get the Edit Controller to use the same validation, OR
Get the Edit page to display the current row's values if I use the same model as the Create page?
e.g.:
My Create page:
#model Test.Models.NewPerson
#using (Html.BeginForm())
{
#Html.ValidationSummary(true, "Failed. Please fix the errors.")
<div class="editor-label">
#Html.LabelFor(m => m.FirstName)
</div>
<div class="editor-field">
#Html.TextBoxFor(m => m.FirstName)
#Html.ValidationMessageFor(m => m.FirstName)
</div>
<div class="editor-label">
#Html.LabelFor(m => m.LastName)
</div>
<div class="editor-field">
#Html.TextBoxFor(m => m.LastName)
#Html.ValidationMessageFor(m => m.LastName)
</div>
<input type="submit" value="Submit" />
}
My Model:
public class NewPerson
{
[Required(ErrorMessage = "*")]
[Display(Name = "First name")]
public string FirstName { get; set; }
[Required(ErrorMessage = "*")]
[Display(Name = "Last name")]
public string LastName { get; set; }
}
Then my Edit page:
#model Test.Person
using (Html.BeginForm())
{
#Html.ValidationSummary(true, "Please fix the errors below.")
<div class="editor-label">
#Html.LabelFor(m => m.FirstName)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.FirstName)
#Html.ValidationMessageFor(m => m.FirstName)
</div>
<div class="editor-label">
#Html.LabelFor(m => m.LastName)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.LastName)
#Html.ValidationMessageFor(m => m.LastName)
</div>
<input type="submit" value="Update" />
}
EDIT
In my controller, Edit action, I have:
var context = new MyContext();
var person = context.Person.Single(m => m.ID == id);
if (Request.IsAjaxRequest())
{
return PartialView("Edit", person);
}
return View(person);
When I put a breakpoint in that function, I am seeing results for var person. However, it returns nothing in the View. Why not?
EDIT
Here is my code for the actions:
[HttpPost]
public ActionResult Create(NewPerson model)
{
if (ModelState.IsValid)
{
string UID = Membership.GetUser().ProviderUserKey.ToString();
System.Guid myUID = System.Guid.Parse(UID);
using (var context = new MyContext())
{
Person newPerson = new Person();
newPerson.UserId = myUID;
newPerson.FirstName = model.FirstName;
newPerson.LastName = model.LastName;
context.Person.AddObject(newPerson);
context.SaveChanges();
}
}
And Edit action:
[HttpGet]
public ActionResult Edit(int id)
{
var context = new MyContext();
//recently edited: accidentally had "camper" instead of "person"
var person = context.Person.Single(m => m.ID == id);
if (Request.IsAjaxRequest())
{
return PartialView("Edit", person);
}
return View(person);
}
And my View:
#foreach (var person in Model)
{
#Html.DisplayFor(modelItem => person.LastName), #Html.DisplayFor(modelItem => person.FirstName)
#Html.ActionLink("Edit", "Edit", new { id = person.ID }, new { #class = "openDialog",
data_dialog_id = "emailDialog", data_dialog_title = "Edit Person" })
}

Answer 1

Both views can use the same model. That is a common practice for Create/Edit functions, and will solve problem 1, having same validation rules.
To display existing data in the input fields on the edit view, you'll need to retrieve that data in the controller and passing it to the view (ie, populate the model).
Presumably, on Edit, you will have an ID of some sort. Use that to get the proper record from the data source, and then set the FirstName and LastName values in the model. Then when you render the view (after passing in the model, of course) you'll see the existing values in the textboxes.

Answer 2

It's a little confusing here as to what you have and haven't done, and what does and doesn't work. However there are a few things that you should fix.
First, you should not be passing the Person object that comes from your database directly to the view. Instead, you should have your own specific Person ViewModel. This ViewModel should have your data annotations for your view on it. When you get the Person from the database, you project them into your ViewModel like this:
var camper = context.Person
.Select(m => new ViewModel.Person
{ Firstname = m.Firstname, Lastname = m.Lastname}).Single(m => m.ID == id);
This prevents your Data model's Person from being bloated by View requirements (for instance, your data model might allow nulls, but you want to set your View to be Required.)
Second, you're not using a using statement in the edit view. Something like this:
using (var camper = ..) {
...
}
Using a ViewModel helps here as well, since this allows the context to be destroyed without conflicting with the entities which are change tracked.
Third, you should probably use DisplayTemplates a little better. Rather than having the foreach statement in your view, do this:
#Html.DisplayForModel()
Then create a folder called DisplayTemplates in Views\Shared (or in the folder your view is in) and create a new .cshtml file called Person.cshtml, in that have this code:
#model Person
#Html.DisplayFor(m => m.LastName), #Html.DisplayFor(m => m.FirstName)
#Html.ActionLink("Edit", "Edit", new { id = person.ID }, new { #class = "openDialog",
data_dialog_id = "emailDialog", data_dialog_title = "Edit Person" })
I also notice some discrepancies in your namespaces. In one place you have Test.Person, in another you have Test.Models.NewPerson. Is it possible that you also have a Test.Models.Person and you're getting confused about which is which, so you end up populating the wrong one?