I'm using DataAnnotations attributes to validate my model objects. My model class looks similar to this:
public class MyModel
{
[Required]
public string Title { get; set; }
[Required(ErrorMessage = "At least one editor is required.")]
public List<User> Editors { get; set; }
}
public class User
{
public int Id { get; set; }
[Required]
public string FullName { get; set; }
[Required]
[DataType(DataType.Email)]
public string Email { get; set; }
}
My controller action looks like:
public ActionResult NewItem(MyModel data)
{
if (!this.Model.IsValid)
{
// invalid processing
}
// valid processing
}
User is presented with a view that has a form with:
- a text box with dummy name where users enter user's names. For each user they enter, there's a client script coupled with ajax that creates an
<input type="hidden" name="Editors[0].Id" value="userId" />for each user entered (enumeration index is therefore not always 0 as written here), so default model binder is able to consume and bind the form without any problems. - a text box where users enter the title
Since I'm using Asp.net MVC 2 RTM which does model validation instead of input validation I don't know how to avoid validation errors. And since users provide User.Id, the whole User object instance is being validated. Which doesn't bother me, as long I would know how to exclude other properties' validation.
The thing is I have to use BindAttribute on my controller action. I would have to either provide a white or a black list of properties. It's always a better practice to provide a white list. It's also more future proof.
The problem
My form works fine, but I get validation errors about user's FullName and Email properties since they are not provided. I also shouldn't feed them to the client (via ajax when user enters user data), because email is personal contact data and is not shared between users.
If there was just a single user reference on MyModel I would write
[Bind(Include = "Title, Editor.Id")]
But I have an enumeration of them. How do I provide Bind white list to work with my model?
One possible solution
I could create a separate view model for User just for the sake of entering MyModel objects. I would put actual validation attributes and omit properties I don't need.
public class MyModelUser
{
[Required]
public int Id { get; set; }
}