ASP.NET MVC 3 - Choose which model property each submit button validates - asp.net

Question

I have a view with three submit buttons. First button must validate some fields, second button must validate other fields, third button doesn't validate anything.
How can I do that on both client (unobtrusive) and server sides?

Answer 1

Most likely with alot of hand rolled usage, especially if you want it to be unobtrusive. You're going to need to create something like <input data-validationgroup="group1"... and then on the click action that your javascript code will then validate what you want. I would imagine jQuery Validate has some type of ruleset support but you'll have to figure that out.
You're going to have to do a similar sequence on the server side, and create ruleset type validation classes/blocks/methods that you interpret the submit action to the relevant ruleset. I'd look at a library like FluentValidation for this part.
To achieve what you want it, is is very extremely unlikely you will be able to achieve this using the DataAnnotations attributes on your model class.

Answer 2

Personally I have always liked and used the FluentValidation.NET library in all my projects. Not only that it is very powerful in terms of expressing validation rules but this library has an excellent integration with ASP.NET MVC. So I will try to provide a sample solution for this problem using it (only server side validation for the moment, later we can talk about unobtrusive client side validation if you want).
So start a new ASP.NET MVC 3 project using the default template and install the FluentValidation.MVC3 NuGet package (the current stable version is 2.0.0.0).
Then let's define a view model:
public class MyViewModel
{
public string Field1 { get; set; }
public string Field2 { get; set; }
}
Now we can assume that if button1 is clicked Field1 is required and if button2 is clicked Field2 is required and if button3 is clicked none of them are required. A fictional scenario but pretty close to your requirements.
Now let's define two different fluent validators for this model corresponding each to button1 and button2:
public class MyModelValidator1 : AbstractValidator<MyViewModel>
{
public MyModelValidator1()
{
RuleFor(x => x.Field1)
.NotEmpty();
}
}
public class MyModelValidator2 : AbstractValidator<MyViewModel>
{
public MyModelValidator2()
{
RuleFor(x => x.Field2)
.NotEmpty();
}
}
Now because it is only at runtime that we know which button is clicked we need to apply the correct validator based on value in the request. So let's write a custom validator provider factory:
public class MyFactory : IValidatorFactory
{
private readonly Func<HttpContextBase> _contextProvider;
public MyFactory(Func<HttpContextBase> contextProvider)
{
_contextProvider = contextProvider;
}
public IValidator GetValidator(Type type)
{
if (type == typeof(MyViewModel))
{
var context = _contextProvider();
if (!string.IsNullOrEmpty(context.Request["button1"]))
{
return new MyModelValidator1();
}
if (!string.IsNullOrEmpty(context.Request["button2"]))
{
return new MyModelValidator2();
}
}
return null;
}
public IValidator<T> GetValidator<T>()
{
return (IValidator<T>)GetValidator(typeof(T));
}
}
and register it in Application_Start:
ModelValidatorProviders.Providers.Add(
new FluentValidationModelValidatorProvider(
new MyFactory(() => new HttpContextWrapper(HttpContext.Current))
)
);
and that's pretty much all. Now what's left is trivial.
A controller:
public class HomeController : Controller
{
public ActionResult Index()
{
var model = new MyViewModel();
return View(model);
}
[HttpPost]
public ActionResult Index(MyViewModel model)
{
if (!ModelState.IsValid)
{
return View(model);
}
return Content("Thanks for submitting", "text/plain");
}
}
and a view:
#model MyViewModel
#using (Html.BeginForm())
{
<div>
#Html.LabelFor(x => x.Field1)
#Html.EditorFor(x => x.Field1)
#Html.ValidationMessageFor(x => x.Field1)
</div>
<div>
#Html.LabelFor(x => x.Field2)
#Html.EditorFor(x => x.Field2)
#Html.ValidationMessageFor(x => x.Field2)
</div>
<input type="submit" value="Submit with button 1" name="button1" />
<input type="submit" value="Submit with button 2" name="button2" />
<input type="submit" value="Submit with button 3" name="button3" />
}