A custom validator which highlights with the colored border

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace MyNamespace
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    [ToolboxData("<{0}:MyCustomValidator runat=\"server\"></{0}:MyCustomValidator>")]
    public class MyCustomValidator : CustomValidator
    {
        public MyCustomValidator()
        {
            this.SetFocusOnError = true;
            this.ValidateEmptyText = true;
        }

        protected override bool EvaluateIsValid()
        {
            string _target = this.ControlToValidate;
            WebControl obj = this.Parent.FindControl(_target) as WebControl;

            if (obj != null)
            {
                string value = this.GetControlValidationValue(_target);
                if (obj.Enabled && (string.IsNullOrEmpty(value) || string.IsNullOrWhiteSpace(value)))
                {
                    obj.BorderColor = Color.LightPink;
                    return false;
                }
                else if (obj.Enabled)
                    obj.BorderColor = ColorTranslator.FromHtml("#a0a0a0");
                else
                    obj.BorderColor = ColorTranslator.FromHtml("#e0e0e0");
            }

            return true;
        }
    }
}