Validating properties in a PropertyGrid control

using System.Windows.Forms; 

namespace WindowsApplication1 

{ 

    public partial class Form1 : Form 

    { 

        public Form1() 

        { 

            InitializeComponent(); 

            //init person object  

            Person person = new Person(); 

            person.FirstName = "George"; 

            person.Age = 33; 

            propertyGrid.SelectedObject = person; 

            propertyGrid.PropertyValueChanged+=  new PropertyValueChangedEventHandler( propertyGrid_PropertyValueChanged ); 

        } 

        private void propertyGrid_PropertyValueChanged(object s, PropertyValueChangedEventArgs e) 

        { 

            if (e.ChangedItem.Label == "Age" && !IsAgeValid((int)e.ChangedItem.Value) ) 

            { 

                // the entered age value is wrong - show error message 

                e.ChangedItem.PropertyDescriptor.SetValue( propertyGrid.SelectedObject, e.OldValue); 

                MessageBox.Show("Wrong age", "Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); 

            } 

        } 

        ///<summary>

        /// Determines whether age is valid 

        /// </summary>  

        /// <param name="age">The age.</param>  

        /// <returns>  

        /// <c>true</c> if is age valid ; otherwise, <c>false</c>. 

        /// </returns>  

        private static bool IsAgeValid( int age ) 

        { 

            return ((age > 0) && (age < 150)); 

        } 

    } 

}