Using Data Annotations to configure WinForm controls as per the constraint set in the model

AnyPersonModel.cs

using System;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace LordOfScripts.Gists.Windows.Forms.Models
{
    // This is your entity model, not necessarily for Entity Framework
    public class AnyPersonModel
    {
        [Key]
        public int AnyPersonId { get; set; } 
        
        [Required, StringLength(40)]
        public string FirstName { get; set; }
        
        [Required, StringLength(50)]    
        public string LastName { get; set; }
    }
}

AnyView.cs

using System;
using System.Windows.Forms;
using LordOfScripts.Gists.Extensions;

namespace LordOfScripts.Gists.Windows.Forms.Views
{
    // This would be any windows forms in which you want to configure your controls to match the
    // constraints you set in your (entity) model
    public partial class AnyView : Form
    {
        public AnyView(AnyPersonModel model)
        {
            InitializeComponent();
            ConfigureConstraints(model);
        }
        
        private void ConfigureConstraints(AnyPersonModel model)
        {
            // Make sure we set the MaxLength of our textboxes to match the entity model constraints
            textBoxFirstName.MaxLength = model.GetAttributeFrom<StringLengthAttribute>("FirstName").MaximumLength;
            textBoxLastName.MaxLength = model.GetAttributeFrom<StringLengthAttribute>("LastName").MaximumLength;
        }
    }
}

DataAnnotationExtensions.cs

using System;
using System.Windows.Forms;

namespace LordOfScripts.Gists.Extensions
{
   public static class DataAnnotationExtensions
   {
      /// <summary>
      /// (extension) Retrieve the <see cref="System.ComponentModel.DataAnnotations"/> attribute from a 
      /// class property.
      /// </summary>
      /// <typeparam name="T">The attribute type, i.e. StringLengthAttribute, MaxLengthAttribute</typeparam>
      /// <param name="instance">the class instance where the property will be inspected</param>
      /// <param name="propertyName">The class property to which the attribute has been applied</param>
      /// <returns>The attribute value</returns>
      /// <example>
      /// var name = player.GetAttributeFrom<DisplayAttribute>("PlayerDescription").Name;
      /// var maxLength = player.GetAttributeFrom<MaxLengthAttribute>("PlayerName").Length;
      /// </example>
      public static T GetAttributeFrom<T>(this object instance, string propertyName) where T : Attribute
      {
          var attrType = typeof(T);
          var property = instance.GetType().GetProperty(propertyName);
          return (T)property.GetCustomAttributes(attrType, false).First();
      }
   }
}