Disable Required validation attribute under certain circumstances

Question

I was wondering if it is possible to disable the Required validation attribute in certain controller actions. I am wondering this because on one of my edit forms I do not require the user to enter values for fields that they have already specified previously. However I then implement logic that when they enter a value it uses some special logic to update the model, such as hashing a value etc.

Any sugestions on how to get around this problem?

EDIT:
And yes client validation is a problem here to, as it will not allow them to submit the form without entering a value.

Answer 1

This problem can be easily solved by using view models. View models are classes that are specifically tailored to the needs of a given view. So for example in your case you could have the following view models:

public UpdateViewView
{
    [Required]
    public string Id { get; set; }

    ... some other properties
}

public class InsertViewModel
{
    public string Id { get; set; }

    ... some other properties
}

which will be used in their corresponding controller actions:

[HttpPost]
public ActionResult Update(UpdateViewView model)
{
    ...
}

[HttpPost]
public ActionResult Insert(InsertViewModel model)
{
    ...
}