Ignore Required attribute when saving on edit page - validation

Question

I have a model class that has a couple of required fields:
public class UserMetadata
{
[Required(ErrorMessage = "Please enter a name.")]
public string Name { get; set; }
[Required(ErrorMessage = "Please enter a password.")]
public string Password { get; set; }
}
On the create view, if I don't give a name and/or password, then the validation summary errors appears. All nice and good. For the edit view, I'm only displaying the 'Name' field - I don't to show the 'Password' field.
When I save my changes on the edit page, the validation summary error appears saying that I must enter a password.
How can I control the validation of the password field, so that for the edit view, it should not bother with it? Or, am I approaching this the wrong way? I still want the 'Name' field validation to work on the edit view.
EDIT:
For my MVC project, I'm using Entity Framework. Thus, I have a 'UserMetadata' class defined so that I can attached things like '[Required]' onto certain fields on the 'User' class (which is in the EDMX file).
I should also explain that I'm using a view model eg 'UserEditViewModel' which has a property 'User' attached to it. So on my post:
[HttpPost]
public ActionResult Edit(UserEditViewModel inputViewModel)
{
if(ModelState.IsValid) { inputViewModel.User blah.... }
}
Think I rushed a bit when typing this question. Any other missing information you think is important, then please give me a shout.
Cheers.
Jas.

Answer 1

I ended up doing this in my action method:
ModelState.Remove("User.Password");
Now my code runs fine, only raising validation errors on the "Name" field, which is what I wanted..

Answer 2

ModelState.Remove("User.Password") did not work for me in MVC 3.
However, the following worked.
Option 1:
ModelState.Remove("Password")
Option 2:
ModelState.Where(m => m.Key == "Password").FirstOrDefault().Value.Errors.Clear()

Answer 3

Assuming you're using your UserMetadata class as a view model, you should be using a different view model per page (view).
e.g.
public class UserMetaDataCreate
{
[Required(ErrorMessage = "Please enter a name.")]
public string Name { get; set; }
[Required(ErrorMessage = "Please enter a password.")]
public string Password { get; set; }
}
and UserMetaDataEdit
public class UserMetaDataEdit
{
[Required(ErrorMessage = "Please enter a name.")]
public string Name { get; set; }
}
Basically, if the edit view doesn't need password, it shouldn't be in the model anyway.
In your controller,
public ActionResult Create()
{
return View(new UserMetaDataCreate());
}
// and subsequent post actions
[HttpPost]
public ActionResult Edit(UserMetaDataEdit vm)
{
if(ModelState.IsValid)
{
// do something
}
else
return View(vm);
}
Of course, you could go about some inheritance as your models become more complex e.g.
public class UserMetaData
{
[Required(ErrorMessage = "Please enter a name.")]
public string Name { get; set; }
}
And subclass your view models
public class UserMetaDataEdit
{
[Required(ErrorMessage = "Please enter a password.")]
public string Password { get; set; }
}
public class UserMetaDataCreate
{
}
But, I'm not sure that makes sense contextually since UserMetaData does semantically include a password.