FluentValidation is a .NET library used for validation in
applications developed using the .NET framework. It provides a fluent interface
for defining validation rules for your classes. With FluentValidation, you can
define validation rules in a clear and expressive way, making your code more
readable and maintainable.
Instead of cluttering your domain classes with validation logic,
you can create separate validator classes that define the validation rules for
each class. This separation of concerns helps keep your codebase clean and
organized.
FluentValidation supports various types of validation rules,
including basic checks like required fields, string length, and numeric range,
as well as more complex validations such as custom validation logic and cross-property
validations.
Overall, FluentValidation simplifies the process of
validating input data in .NET applications and promotes clean, maintainable
code by separating validation concerns from domain logic.
Create a project named FluentValidationTest.
Run this commands to install fluent validation :
-
Install-Package FluentValidation
-
Install-Package
FluentValidation.AspNetCore
-
Install-Package
FluentValidation.DependencyInjectionExtensions
In Program.cs file add this lines:
builder.Services.AddFluentValidation(v
=>
{
v.RegisterValidatorsFromAssembly(Assembly.GetExecutingAssembly());
});
In Models Folder create a class named it “CustomerModel”
public class CustomerModel
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public decimal Height { get; set; }
public int Age { get; set; }
public string Phone { get; set; }
public AddressModel PrimaryAddress { get; set; }
public List<AddressModel> OtherAddresses { get; set; }
}
Create a directory named Validators
Create a class named CustomerValidator.cs
public class CustomerValidator : AbstractValidator<CustomerModel>
{
public CustomerValidator()
{
//RuleFor(x => x.FirstName).NotNull().NotEmpty();
//RuleFor(x => x.LastName).NotNull().NotEmpty();
RuleFor(x => x.FirstName).NotEmpty().WithMessage("First Name is
required.");
RuleFor(x => x.LastName).NotEmpty().WithMessage("Last Name is
required.");
RuleFor(x => x.Email).NotNull().NotEmpty().EmailAddress();
RuleFor(x =>
x.Height).ScalePrecision(1, 3);
RuleFor(x => x.Age).InclusiveBetween(18, 50);
RuleFor(x => x.Phone).Must(phone =>
!string.IsNullOrEmpty(phone)
&& phone.StartsWith("+")
).WithMessage("Phone must starts with + sign.");
RuleFor(x => x.PrimaryAddress).InjectValidator();
// You can also specify any child validators for complex properties
// by using the SetValidator method.
RuleFor(x => x.PrimaryAddress).SetValidator(new AddressValidator());
// To validator the OtherAddresses collection, you can use the RuleForEach
// method to associate the same validator to
multiple items in a collection.
RuleForEach(x => x.OtherAddresses).SetValidator(new AddressValidator());
}
}
Create a controller CustomerController
Add this controller:
public IActionResult Create()
{
return View();
}
[HttpPost]
public IActionResult Create(CustomerModel
model)
{
if (!ModelState.IsValid)
{
return View(model);
}
//TODO: Save the customer to the database.
return Ok();
}
Create view:
@model FluentValidationTest.Models.CustomerModel
@{
ViewData["Title"] = "Create";
Layout = "~/Views/Shared/_Layout.cshtml";
}
<h3>Add
Customer</h3>
<hr />
<form asp-action="Create" method="post">
<div class="row">
<div class="col-md-6">
<div class="form-group">
<label>First
Name</label>
<input asp-for="FirstName" class="form-control" />
<span asp-validation-for="FirstName" class="text-danger"></span>
</div>
</div>
<div class="col-md-6">
<div class="form-group">
<label>Last
Name</label>
<input asp-for="LastName" class="form-control" />
<span asp-validation-for="LastName" class="text-danger"></span>
</div>
</div>
</div>
<div class="row">
<div class="col-md-6">
<div class="form-group">
<label>Email</label>
<input asp-for="Email" class="form-control" />
<span asp-validation-for="Email" class="text-danger"></span>
</div>
</div>
<div class="col-md-6">
<div class="form-group">
<label>Height</label>
<input asp-for="Height" class="form-control" />
<span asp-validation-for="Height" class="text-danger"></span>
</div>
</div>
</div>
<div class="row">
<div class="col-md-6">
<div class="form-group">
<label>Age</label>
<input asp-for="Age" class="form-control" />
<span asp-validation-for="Age" class="text-danger"></span>
</div>
</div>
<div class="col-md-6">
<div class="form-group">
<label>Phone</label>
<input asp-for="Phone" class="form-control" />
<span asp-validation-for="Phone" class="text-danger"></span>
</div>
</div>
</div>
<div class="row">
<div class="col-md-6">
<div class="form-group">
<input type="submit" value="Create" class="btn btn-primary" />
</div>
</div>
</div>
</form>
For details please visit:
https://docs.fluentvalidation.net/en/latest/inheritance.html
Github: https://github.com/itsjubayer/ASP.NET-FluentValidation-.git
