The Asp.net MVC 3 statement excludes some field validation in TryUpdateModel

Question

I use ASP.NET MVC Razor And Data Annotation validators. My model:

public class Person { public int id { get; set; } [Required] public string FirstName { get; set; } [Required] public string LastName { get; set; } } 

FirstName And LastName - Requerd. I want to change FirstName. My method:

 public ActionResult Edit([Bind(Include = "FirstName")]Person person) { var p = GetPerson(); if (TryUpdateModel(p)) { //Save Changes; } } 

But TryUpdateModel always returns false. because LastName is not valid.

How to prevent LastName validation check in TryUpdateModel?

Note:

• The code is simplified. my real code is very complicated.
• I need to use Requierd for two properties
• I do not want to use another model class

Answer 1

I found Nice Solution. I have to remove an unused field from ModelState. then ModelState.IsValid returns true. first I need to create a new attribute class:

 public class ValidateOnlyIncomingValuesAttribute : ActionFilterAttribute { public override void OnActionExecuting(ActionExecutingContext filterContext) { var modelState = filterContext.Controller.ViewData.ModelState; var valueProvider = filterContext.Controller.ValueProvider; var keysWithNoIncomingValue = modelState.Keys.Where( x=>!valueProvider.ContainsPrefix(x) ); foreach (var key in keysWithNoIncomingValue) modelState[key].Errors.Clear(); } } 

then I will add an attribute to my method:

 [ValidateOnlyIncomingValuesAttribute] public ActionResult Edit([Bind(Include = "FirstName")]Person person) { var p = GetPerson(); if (ModelState.IsValid) { TryUpdateModel(p); //Save Changes; } } 

Take a look at this: http://blog.stevensanderson.com/2010/02/19/partial-validation-in-aspnet-mvc-2/

Answer 2

You can remove properties that you don’t need before checking if the model is really

 ModelState.Remove("Email"); if (ModelState.IsValid) { // whatever you want to do } 

Answer 3

A very simple solution that I found out.

 public ActionResult Edit(Person person) { ModelState.Remove("FirstName"); // This will remove the key var p = GetPerson(); if (TryUpdateModel(p)) { //Save Changes; } } } 

Answer 4

Short answer: you cannot use default data annotations.

Longer answer: you have several options.

• You can create your own validator annotations.
• You can make your class class inherit from ivalidatableObject, and then implement the Validate method. (however, this is not a client-side check).
• You can use a third-party validation library, such as FluentValidation.
• You can create another model for this scenario.
• You can remove the validation and simply add code to your action method, which validates the fields. (this is not recommended, as it increases the complexity of your controller’s actions, and you need to duplicate this functionality wherever you use this model).