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

namespace TM
{
    public class ValidatedClassExample : Screen, INotifyDataErrorInfo
    {
        public event PropertyChangedEventHandler PropertyChanged;
        public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged;


        private ValidatorComponent _validatorComponent;

        protected ValidatingScreen()
        {
            _validatorComponent = new ValidatorComponent(this);
            _validatorComponent.ErrorsChanged += PropagateErrorsChanged;
        }

        private void PropagateErrorsChanged(object sender, DataErrorsChangedEventArgs e)
        {
            ErrorsChanged?.Invoke(this, e);
        }

        public virtual bool HasErrors => _validatorComponent.HasErrors;

        public virtual System.Collections.IEnumerable GetErrors(string propertyName) => _validatorComponent.GetErrors(propertyName);


        private void NotifyOfPropertyChange(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }


        #region some validated properties

        [Required]
        public string MyString
        {
            get { return _myString; }
            set
            {
                if (value == _myString)
                    return;
                _myString = value;
                NotifyOfPropertyChange(nameof(MyString));
            }
        }
        private string _myString;

        #endregion

    }
}