CODEWITHSUNDEEP
c#.netasp.net-mvcvalidationfluentvalidation
Cybercop
Cybercop

Reputation: 8678

FluentValidation: Check if one of two fields are empty

I have this model

public class Person
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }  
}

I want to create a validation where either FirstName or LastName must be filled in by user. I installed FluentValidation and created a customvalidator class

public class PersonValidator:AbstractValidator<Person>
{
    public PersonValidator()
    {
        RuleFor((person=>person.FirstName)//don't know how to check if one is empty
    }
}

To check just one field I could just do RuleFor(person => person.FirstName).NotNull();

But how do I check if one of them is null.

Also, is it possible, once validation is created via fluentValidation, use it on the client side to show error?

Edit1

    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();

        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);
        BundleConfig.RegisterBundles(BundleTable.Bundles);
        FluentValidationModelValidatorProvider.Configure();
    }
//creating validation
namespace WebApplication1.Models.CustomValidator
{
    public class PersonValidator:AbstractValidator<Person>
    {
        public PersonValidator()
        {
            RuleFor(m => m.FirstName).NotEmpty().When(m => string.IsNullOrEmpty(m.LastName)).WithMessage("*Either First Name or Last Name is required");
            RuleFor(m => m.LastName).NotEmpty().When(m => string.IsNullOrEmpty(m.FirstName)).WithMessage("*Either First Name or Last Name is required");
        }
    }

}
//model class
[Validator(typeof(PersonValidator))]
public class Person
{
    public Person()
    {
        InterestList = new List<string>();
    }
    public int Id { get; set; }
    public int ContactId { get; set; }
    [RequiredIfEmpty("LastName")]
    public string FirstName { get; set; }
    [RequiredIfEmpty("FirstName")]
    public string LastName { get; set; }
    public string EmailAddress { get; set; }
    public string Phone { get; set; }
    public string Country { get; set; }
    public List<string> InterestList { get; set; } 
}
//view
@model WebApplication1.Models.Person

<script src="@Url.Content("~/Scripts/jquery-1.8.2.min.js")"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.min.js")"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")"></script>
<script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script>

@Html.ValidationSummary(true)
@using(Html.BeginForm("AddPerson","Person",FormMethod.Post))
{
    <div class="label">First Name</div>
    <div class="input-block-level">@Html.TextBoxFor(m=>m.FirstName)@Html.ValidationMessageFor(m=>m.FirstName)</div>
    <br/>
    <div class="label">Last Name</div>
    <div class="input-block-level">@Html.TextBoxFor(m=>m.LastName)@Html.ValidationMessageFor(m=>m.LastName)</div>
    <button type="submit" class="btn-primary">Submit</button>
}

Upvotes: 83

Views: 79791

Answers (7)

Armend Ukehaxhaj
Armend Ukehaxhaj

Reputation: 657

For people who have similar cases but with more properties (e.g. two fields out of four need to have a value), you can use something like this:

public class PersonValidator : AbstractValidator<Person>
{
    public PersonValidator()
    {
        RuleFor(person => person)
            .Must(MustHaveAtLeastTwoProperties)
            .WithMessage("Random validation message");
    }

    private bool MustHaveAtLeastTwoProperties(Person person)
    {
        return new[] { person.FirstName, person.LastName, person.Address1, person.Address2 } // Added Address1 and Address2 as new string properties
            .Count(prop => !string.IsNullOrWhiteSpace(prop)) >= 2; // Set to how many properties you want to have a value
    }
}

Upvotes: 1

dummyDev
dummyDev

Reputation: 461

A nice rule-set to check if one of two fields are empty, as well as coming up with meaningful error codes is the following:

public CustomerSourceValidator()
    {
        CascadeMode = CascadeMode.StopOnFirstFailure;

        RuleFor(x => x)
            .NotNull().WithErrorCode("source_id_or_email_required")
            .When(source => source.Email == null && source.Id == null);

        RuleFor(x => x.Id)
            .NotNull().WithErrorCode("source_id_required")
            .Matches(CommonValidationRegex.CustomerIdRegexString).WithErrorCode("source_id_invalid")
            .When(source => source.Id != null);

        RuleFor(x => x.Email)
            .NotNull().WithErrorCode("source_email_required")
            .Matches(CommonValidationRegex.EmailRegexString).WithErrorCode("source_email_invalid")
            .When(source => source.Email != null);
    }

Upvotes: 1

Zabavsky
Zabavsky

Reputation: 13640

You can use When/Unless condition:

RuleFor(m => m.FirstName).NotEmpty().When(m => string.IsNullOrEmpty(m.LastName));
RuleFor(m => m.LastName).NotEmpty().When(m => string.IsNullOrEmpty(m.FirstName));

or

RuleFor(m => m.FirstName).NotEmpty().Unless(m => !string.IsNullOrEmpty(m.LastName));
RuleFor(m => m.LastName).NotEmpty().Unless(m => !string.IsNullOrEmpty(m.FirstName));

As for your second question, FluentValidation works with client-side validation, but not all rules are supported. Here you can find validators, that are supported on the client-side:

  1. NotNull/NotEmpty
  2. Matches (regex)
  3. InclusiveBetween (range)
  4. CreditCard
  5. Email
  6. EqualTo (cross-property equality comparison)
  7. Length

For rules that are not in the list you have to write your own FluentValidationPropertyValidator and implement GetClientValidationRules. You can find a few samples of this on the StackOverflow by doing simple search.

Upvotes: 141

Nishith Shah
Nishith Shah

Reputation: 393

Finally, this worked for me. I wanted to validate three properties where at least one is required. It returns an error message only once.

RuleFor(p => p).Cascade(CascadeMode.StopOnFirstFailure)
            .Must(p => !string.IsNullOrWhiteSpace(p.FirstName))
            .When(p => p.Id == 0 && string.IsNullOrWhiteSpace(p.LastName)).WithMessage("At least one is required (Id, FirstName, LastName).")
            .Must(p => !string.IsNullOrWhiteSpace(p.LastName))
            .When(p => p.Id == 0 && string.IsNullOrWhiteSpace(p.FirstName)).WithMessage("At least one is required (Id, FirstName, LastName).")
            .Must(p => p.Id != 0)
            .When(p => string.IsNullOrWhiteSpace(p.FirstName) && string.IsNullOrWhiteSpace(p.LastName)).WithMessage("At least one is required (Id, FirstName, LastName).");

Upvotes: 5

RAVI VAGHELA
RAVI VAGHELA

Reputation: 897

I did like this to check charges entered are same to previous one or not. If charges are same as previous one than it'll give an error. This worked for me.

public class CasualMealChargeValidator : AbstractValidator<CasualMealCharge>
{
    public CasualMealChargeValidator(CasualMealCharge CMC)
    {
        //RuleFor(x => x.BankName).NotEmpty().When(pm => pm.PaymentMode == "Cheque").WithMessage("Enter Bank.");
        RuleFor(x => x).Must(x => x.DN != CMC.DN || x.BF != CMC.BF || x.LN != CMC.LN).WithMessage("Not Saved - Meal charges are same as current charges.").WithName("CMFor");
    }
}

Upvotes: 6

Fat Shogun
Fat Shogun

Reputation: 1047

Try this

RuleFor(person => person).Must(person => !string.IsNullOrEmpty(person.FirstName) || !string.IsNullOrEmpty(person.LastName))

Upvotes: 22

Carsten Heine
Carsten Heine

Reputation: 144

I don't know that library, but if you just want to check those two properties for null, then you can use this:

RuleFor(person => person.FirstName ?? person.LastName).NotNull();

EDIT This doesn't work, because it throws an InvalidOperationException. Use Zabavsky's solution instead.

Upvotes: 2

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