GridView, How do I change a cell's value based on a change in another cell?

        Dictionary<int,string> statuses= new Dictionary<int,string>();
        public RadForm1()
        {
            InitializeComponent();
            statuses.Add(1, "A new item that needs to be reviewed and triaged by the team.");
            statuses.Add(2, "The team is currently working on this item.");
            statuses.Add(3, "Implemented. Refer to the item for information about the release this is included in.");

            DataTable dt = new DataTable();
            dt.Columns.Add("Id", typeof(int));
            dt.Columns.Add("Name", typeof(string));
            dt.Rows.Add(1, "Pending Review");
            dt.Rows.Add(2, "In Development");
            dt.Rows.Add(3, "Completed");

            GridViewComboBoxColumn comboColumn = new GridViewComboBoxColumn("Status"); 
            comboColumn.DataSource = dt;
            comboColumn.ValueMember = "Id";
            comboColumn.DisplayMember = "Name"; 
            comboColumn.Width = 200;
            this.radGridView1.Columns.Add(comboColumn);

            GridViewTextBoxColumn descriptionColumn = new GridViewTextBoxColumn("Description");
            this.radGridView1.Columns.Add(descriptionColumn);
            this.radGridView1.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill;

            this.radGridView1.CellEditorInitialized += RadGridView1_CellEditorInitialized;

            BindingList<Item> items = new BindingList<Item>();
            items.Add(new Item(2, statuses[2])); ;
        }

        private void RadGridView1_CellEditorInitialized(object sender, GridViewCellEventArgs e)
        {
            RadDropDownListEditor editor = e.ActiveEditor as RadDropDownListEditor;
            if (editor != null)
            {
                RadDropDownListEditorElement el = editor.EditorElement as RadDropDownListEditorElement;
                el.SelectedValueChanged -= El_SelectedValueChanged;
                el.SelectedValueChanged += El_SelectedValueChanged;
            }
        }

        private void El_SelectedValueChanged(object sender, Telerik.WinControls.UI.Data.ValueChangedEventArgs e)
        {
            if (e.NewValue!=null)
            {
                int id = (int)e.NewValue;
                if (statuses.ContainsKey(id))
                {
                    this.radGridView1.CurrentRow.Cells["Description"].Value = statuses[id];
                }
            }
        }

        public class Item : System.ComponentModel.INotifyPropertyChanged
        {
            int s_id;
            string m_name; 
            public event PropertyChangedEventHandler PropertyChanged;
            public Item(int s_id, string m_description)
            {
                this.s_id = s_id;
                this.m_name = m_description;
                 
            }
            public int Id
            {
                get
                {
                    return s_id;
                }
                set
                {
                    if (this.s_id != value)
                    {
                        this.s_id = value;
                        OnPropertyChanged("Id");
                    }
                }
            }
            public string Name
            {
                get
                {
                    return m_name;
                }
                set
                {
                    if (this.m_name != value)
                    {
                        this.m_name = value;
                        OnPropertyChanged("Name");
                    }
                }
            }
          
            protected virtual void OnPropertyChanged(string propertyName)
            {
                if (PropertyChanged != null)
                {
                    PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
                }
            }
        }