Hướng dẫn sử dụng thư viện FluentValidation để kiểm tra Form nhập liệu winform

if(String.IsNullOrEmpty(txtName.Text)
{
   MessageBox.Show("Vui lòng nhập tên của bạn.");
   return;
}

PM> Install-Package FluentValidation -Version 9.3.0

using FluentValidation;
using FluentValidation.Results;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace FluentValidateDemo
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnSave_Click(object sender, EventArgs e)
        {
            var student = new Student();
            student.ID = txtID.Text;
            student.Name = txtName.Text;
            student.Email = txtEmail.Text;
            student.Address = txtAddress.Text;
            student.Phone = txtPhone.Text;
            var validator = new StudentValidator();

            ValidationResult results = validator.Validate(student);
            errorProvider.Clear();
            if (!results.IsValid)
            {
                foreach (var failure in results.Errors)
                {
                    switch (failure.PropertyName)
                    {
                        case "ID":
                            errorProvider.SetError(txtID, failure.ErrorMessage);
                            txtID.BorderColor = Color.Red;
                            break;
                        case "Name":
                            errorProvider.SetError(txtName, failure.ErrorMessage);
                            txtName.BorderColor = Color.Red;
                            break;
                        case "Email":
                            errorProvider.SetError(txtEmail, failure.ErrorMessage);
                            txtEmail.BorderColor = Color.Red;
                            break;
                        case "Address":
                            errorProvider.SetError(txtAddress, failure.ErrorMessage);
                            txtAddress.BorderColor = Color.Red;
                            break;
                        case "Phone":
                            errorProvider.SetError(txtPhone, failure.ErrorMessage);
                            txtPhone.BorderColor = Color.Red;
                            break;
                    }                   
                   
                }
                
                if(!results.Errors.ToList().Exists(x => x.PropertyName == "ID"))
                {
                    successProvider.SetError(txtID, "Pass");
                    txtID.BorderColor = Color.Green;
                }
                if (!results.Errors.ToList().Exists(x => x.PropertyName == "Name"))
                {
                    successProvider.SetError(txtName, "Pass");
                    txtName.BorderColor = Color.Green;
                }
                if (!results.Errors.ToList().Exists(x => x.PropertyName == "Email"))
                {
                    successProvider.SetError(txtEmail, "Pass");
                    txtEmail.BorderColor = Color.Green;
                }
                if (!results.Errors.ToList().Exists(x => x.PropertyName == "Address"))
                {
                    successProvider.SetError(txtAddress, "Pass");
                    txtAddress.BorderColor = Color.Green;
                }
                if (!results.Errors.ToList().Exists(x => x.PropertyName == "Phone"))
                {
                    successProvider.SetError(txtPhone, "Pass");
                    txtPhone.BorderColor = Color.Green;
                }


            }
            else
            {
                MessageBox.Show("Pass validate Form.");
            }
           
        }
       
        public class Student
        {
            public string ID { set; get; }
            public string Name { set; get; }
            public string Email { set; get; }
            public string Address { set; get; }
            public string Phone { set; get; }
        }

        public class StudentValidator : AbstractValidator<Student>
        {
            public StudentValidator()
            {
                RuleFor(x => x.ID)
                        .NotEmpty().WithMessage("Enter your ID.");

                RuleFor(x => x.Name)
                        .NotEmpty().WithMessage("Enter your Name.");

                RuleFor(x => x.Email)
                .NotEmpty().WithMessage("Email address is required")
                .EmailAddress().WithMessage("Email is not valid");              

                RuleFor(x => x.Address).Length(10, 100).WithMessage("Please specify a valid Address");
                RuleFor(x => x.Phone)
                       .NotEmpty().WithMessage("Phone is required")
                       .Length(10, 11).WithMessage("Please specify a valid Phone");

            }
        }
    }
}